--- a/dom/base/ChildIterator.cpp
+++ b/dom/base/ChildIterator.cpp
@@ -3,17 +3,16 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
  * You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "ChildIterator.h"
 #include "nsContentUtils.h"
 #include "mozilla/dom/XBLChildrenElement.h"
 #include "mozilla/dom/HTMLContentElement.h"
-#include "mozilla/dom/HTMLShadowElement.h"
 #include "mozilla/dom/ShadowRoot.h"
 #include "nsIAnonymousContentCreator.h"
 #include "nsIFrame.h"
 #include "nsCSSAnonBoxes.h"
 
 namespace mozilla {
 namespace dom {
 
@@ -73,27 +72,16 @@ ExplicitChildIterator::GetNextChild()
     MOZ_ASSERT(!mDefaultChild);
 
     MatchedNodes assignedChildren = GetMatchedNodesForPoint(mChild);
     if (mIndexInInserted < assignedChildren.Length()) {
       return assignedChildren[mIndexInInserted++];
     }
     mIndexInInserted = 0;
     mChild = mChild->GetNextSibling();
-  } else if (mShadowIterator) {
-    // If we're inside of a <shadow> element, look through the
-    // explicit children of the projected ShadowRoot via
-    // the mShadowIterator.
-    nsIContent* nextChild = mShadowIterator->GetNextChild();
-    if (nextChild) {
-      return nextChild;
-    }
-
-    mShadowIterator = nullptr;
-    mChild = mChild->GetNextSibling();
   } else if (mDefaultChild) {
     // If we're already in default content, check if there are more nodes there
     MOZ_ASSERT(mChild);
     MOZ_ASSERT(nsContentUtils::IsContentInsertionPoint(mChild));
 
     mDefaultChild = mDefaultChild->GetNextSibling();
     if (mDefaultChild) {
       return mDefaultChild;
@@ -105,33 +93,17 @@ ExplicitChildIterator::GetNextChild()
     mIsFirst = false;
   } else if (mChild) { // in the middle of the child list
     mChild = mChild->GetNextSibling();
   }
 
   // Iterate until we find a non-insertion point, or an insertion point with
   // content.
   while (mChild) {
-    // If the current child being iterated is a shadow insertion point then
-    // the iterator needs to go into the projected ShadowRoot.
-    if (ShadowRoot::IsShadowInsertionPoint(mChild)) {
-      // Look for the next child in the projected ShadowRoot for the <shadow>
-      // element.
-      HTMLShadowElement* shadowElem = HTMLShadowElement::FromContent(mChild);
-      ShadowRoot* projectedShadow = shadowElem->GetOlderShadowRoot();
-      if (projectedShadow) {
-        mShadowIterator = new ExplicitChildIterator(projectedShadow);
-        nsIContent* nextChild = mShadowIterator->GetNextChild();
-        if (nextChild) {
-          return nextChild;
-        }
-        mShadowIterator = nullptr;
-      }
-      mChild = mChild->GetNextSibling();
-    } else if (nsContentUtils::IsContentInsertionPoint(mChild)) {
+    if (nsContentUtils::IsContentInsertionPoint(mChild)) {
       // If the current child being iterated is a content insertion point
       // then the iterator needs to return the nodes distributed into
       // the content insertion point.
       MatchedNodes assignedChildren = GetMatchedNodesForPoint(mChild);
       if (!assignedChildren.IsEmpty()) {
         // Iterate through elements projected on insertion point.
         mIndexInInserted = 1;
         return assignedChildren[0];
@@ -191,21 +163,19 @@ FlattenedChildIterator::Init(bool aIgnor
 
 bool
 ExplicitChildIterator::Seek(nsIContent* aChildToFind)
 {
   if (aChildToFind->GetParent() == mParent &&
       !aChildToFind->IsRootOfAnonymousSubtree()) {
     // Fast path: just point ourselves to aChildToFind, which is a
     // normal DOM child of ours.
-    MOZ_ASSERT(!ShadowRoot::IsShadowInsertionPoint(aChildToFind));
     MOZ_ASSERT(!nsContentUtils::IsContentInsertionPoint(aChildToFind));
     mChild = aChildToFind;
     mIndexInInserted = 0;
-    mShadowIterator = nullptr;
     mDefaultChild = nullptr;
     mIsFirst = false;
     return true;
   }
 
   // Can we add more fast paths here based on whether the parent of aChildToFind
   // is a shadow insertion point or content insertion point?
 
@@ -216,41 +186,33 @@ ExplicitChildIterator::Seek(nsIContent* 
 nsIContent*
 ExplicitChildIterator::Get() const
 {
   MOZ_ASSERT(!mIsFirst);
 
   if (mIndexInInserted) {
     MatchedNodes assignedChildren = GetMatchedNodesForPoint(mChild);
     return assignedChildren[mIndexInInserted - 1];
-  } else if (mShadowIterator)  {
-    return mShadowIterator->Get();
   }
+
   return mDefaultChild ? mDefaultChild : mChild;
 }
 
 nsIContent*
 ExplicitChildIterator::GetPreviousChild()
 {
   // If we're already in the inserted-children array, look there first
   if (mIndexInInserted) {
     // NB: mIndexInInserted points one past the last returned child so we need
     // to look *two* indices back in order to return the previous child.
     MatchedNodes assignedChildren = GetMatchedNodesForPoint(mChild);
     if (--mIndexInInserted) {
       return assignedChildren[mIndexInInserted - 1];
     }
     mChild = mChild->GetPreviousSibling();
-  } else if (mShadowIterator) {
-    nsIContent* previousChild = mShadowIterator->GetPreviousChild();
-    if (previousChild) {
-      return previousChild;
-    }
-    mShadowIterator = nullptr;
-    mChild = mChild->GetPreviousSibling();
   } else if (mDefaultChild) {
     // If we're already in default content, check if there are more nodes there
     mDefaultChild = mDefaultChild->GetPreviousSibling();
     if (mDefaultChild) {
       return mDefaultChild;
     }
 
     mChild = mChild->GetPreviousSibling();
@@ -260,32 +222,17 @@ ExplicitChildIterator::GetPreviousChild(
     mChild = mChild->GetPreviousSibling();
   } else { // at the end of the child list
     mChild = mParent->GetLastChild();
   }
 
   // Iterate until we find a non-insertion point, or an insertion point with
   // content.
   while (mChild) {
-    if (ShadowRoot::IsShadowInsertionPoint(mChild)) {
-      // If the current child being iterated is a shadow insertion point then
-      // the iterator needs to go into the projected ShadowRoot.
-      HTMLShadowElement* shadowElem = HTMLShadowElement::FromContent(mChild);
-      ShadowRoot* projectedShadow = shadowElem->GetOlderShadowRoot();
-      if (projectedShadow) {
-        // Create a ExplicitChildIterator that begins iterating from the end.
-        mShadowIterator = new ExplicitChildIterator(projectedShadow, false);
-        nsIContent* previousChild = mShadowIterator->GetPreviousChild();
-        if (previousChild) {
-          return previousChild;
-        }
-        mShadowIterator = nullptr;
-      }
-      mChild = mChild->GetPreviousSibling();
-    } else if (nsContentUtils::IsContentInsertionPoint(mChild)) {
+    if (nsContentUtils::IsContentInsertionPoint(mChild)) {
       // If the current child being iterated is a content insertion point
       // then the iterator needs to return the nodes distributed into
       // the content insertion point.
       MatchedNodes assignedChildren = GetMatchedNodesForPoint(mChild);
       if (!assignedChildren.IsEmpty()) {
         mIndexInInserted = assignedChildren.Length();
         return assignedChildren[mIndexInInserted - 1];
       }

--- a/dom/base/ChildIterator.h
+++ b/dom/base/ChildIterator.h
@@ -43,26 +43,22 @@ public:
       mIsFirst(aStartAtBeginning),
       mIndexInInserted(0)
   {
   }
 
   ExplicitChildIterator(const ExplicitChildIterator& aOther)
     : mParent(aOther.mParent), mChild(aOther.mChild),
       mDefaultChild(aOther.mDefaultChild),
-      mShadowIterator(aOther.mShadowIterator ?
-                      new ExplicitChildIterator(*aOther.mShadowIterator) :
-                      nullptr),
       mIsFirst(aOther.mIsFirst),
       mIndexInInserted(aOther.mIndexInInserted) {}
 
   ExplicitChildIterator(ExplicitChildIterator&& aOther)
     : mParent(aOther.mParent), mChild(aOther.mChild),
       mDefaultChild(aOther.mDefaultChild),
-      mShadowIterator(Move(aOther.mShadowIterator)),
       mIsFirst(aOther.mIsFirst),
       mIndexInInserted(aOther.mIndexInInserted) {}
 
   nsIContent* GetNextChild();
 
   // Looks for aChildToFind respecting insertion points until aChildToFind is
   // found.  This version can take shortcuts that the two-argument version
   // can't, so can be faster (and in fact can be O(1) instead of O(N) in many
@@ -111,21 +107,16 @@ protected:
   nsIContent* mChild;
 
   // If non-null, this points to the current default content for the current
   // insertion point that we're iterating (i.e. mChild, which must be an
   // nsXBLChildrenElement or HTMLContentElement). Once this transitions back
   // to null, we continue iterating at mChild's next sibling.
   nsIContent* mDefaultChild;
 
-  // If non-null, this points to an iterator of the explicit children of
-  // the ShadowRoot projected by the current shadow element that we're
-  // iterating.
-  nsAutoPtr<ExplicitChildIterator> mShadowIterator;
-
   // A flag to let us know that we haven't started iterating yet.
   bool mIsFirst;
 
   // If not zero, we're iterating inserted children for an insertion point. This
   // is an index into mChild's inserted children array (mChild must be an
   // nsXBLChildrenElement). The index is one past the "current" child (as
   // opposed to mChild which represents the "current" child).
   uint32_t mIndexInInserted;

--- a/dom/base/DocumentFragment.cpp
+++ b/dom/base/DocumentFragment.cpp
@@ -106,19 +106,17 @@ DocumentFragment::Constructor(const Glob
   if (!window || !window->GetDoc()) {
     aRv.Throw(NS_ERROR_FAILURE);
     return nullptr;
   }
 
   return window->GetDoc()->CreateDocumentFragment();
 }
 
-NS_IMPL_CYCLE_COLLECTION_INHERITED(DocumentFragment,
-                                   FragmentOrElement,
-                                   mHost)
+NS_IMPL_CYCLE_COLLECTION_INHERITED(DocumentFragment, FragmentOrElement, mHost)
 
 // QueryInterface implementation for DocumentFragment
 NS_INTERFACE_MAP_BEGIN(DocumentFragment)
   NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
   NS_INTERFACE_MAP_ENTRIES_CYCLE_COLLECTION(DocumentFragment)
   NS_INTERFACE_MAP_ENTRY(nsIContent)
   NS_INTERFACE_MAP_ENTRY(nsINode)
   NS_INTERFACE_MAP_ENTRY(nsIDOMDocumentFragment)

--- a/dom/base/DocumentFragment.h
+++ b/dom/base/DocumentFragment.h
@@ -38,18 +38,17 @@ public:
   using FragmentOrElement::GetFirstChild;
   using nsINode::QuerySelector;
   using nsINode::QuerySelectorAll;
   // Make sure bindings can see our superclass' protected GetElementById method.
   using nsINode::GetElementById;
 
   // nsISupports
   NS_DECL_ISUPPORTS_INHERITED
-  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(DocumentFragment,
-                                           FragmentOrElement)
+  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(DocumentFragment, FragmentOrElement)
 
   // interface nsIDOMNode
   NS_FORWARD_NSIDOMNODE_TO_NSINODE
 
   // interface nsIDOMDocumentFragment
   NS_DECL_NSIDOMDOCUMENTFRAGMENT
 
   explicit DocumentFragment(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
@@ -117,25 +116,19 @@ public:
     NS_ASSERTION(false, "Trying to unbind a fragment from a tree");
   }
 
   virtual Element* GetNameSpaceElement() override
   {
     return nullptr;
   }
 
-  Element* GetHost() const
-  {
-    return mHost;
-  }
+  Element* GetHost() const { return mHost; }
 
-  void SetHost(Element* aHost)
-  {
-    mHost = aHost;
-  }
+  void SetHost(Element* aHost) { mHost = aHost; }
 
   static already_AddRefed<DocumentFragment>
   Constructor(const GlobalObject& aGlobal, ErrorResult& aRv);
 
 #ifdef DEBUG
   virtual void List(FILE* out, int32_t aIndent) const override;
   virtual void DumpContent(FILE* out, int32_t aIndent, bool aDumpAll) const override;
 #endif

--- a/dom/base/Element.cpp
+++ b/dom/base/Element.cpp
@@ -1101,16 +1101,21 @@ Element::RemoveFromIdTable()
       doc->RemoveFromIdTable(this, id);
     }
   }
 }
 
 already_AddRefed<ShadowRoot>
 Element::CreateShadowRoot(ErrorResult& aError)
 {
+  if (GetShadowRoot()) {
+    aError.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
+    return nullptr;
+  }
+
   nsAutoScriptBlocker scriptBlocker;
 
   RefPtr<mozilla::dom::NodeInfo> nodeInfo;
   nodeInfo = mNodeInfo->NodeInfoManager()->GetNodeInfo(
     nsGkAtoms::documentFragmentNodeName, nullptr, kNameSpaceID_None,
     nsIDOMNode::DOCUMENT_FRAGMENT_NODE);
 
   RefPtr<nsXBLDocumentInfo> docInfo = new nsXBLDocumentInfo(OwnerDoc());
@@ -1137,34 +1142,17 @@ Element::CreateShadowRoot(ErrorResult& a
   // Calling SetPrototypeBinding takes ownership of protoBinding.
   docInfo->SetPrototypeBinding(NS_LITERAL_CSTRING("shadowroot"), protoBinding);
 
   RefPtr<ShadowRoot> shadowRoot = new ShadowRoot(this, nodeInfo.forget(),
                                                    protoBinding);
 
   shadowRoot->SetIsComposedDocParticipant(IsInComposedDoc());
 
-  // Replace the old ShadowRoot with the new one and let the old
-  // ShadowRoot know about the younger ShadowRoot because the old
-  // ShadowRoot is projected into the younger ShadowRoot's shadow
-  // insertion point (if it exists).
-  ShadowRoot* olderShadow = GetShadowRoot();
   SetShadowRoot(shadowRoot);
-  if (olderShadow) {
-    olderShadow->SetYoungerShadow(shadowRoot);
-
-    // Unbind children of older shadow root because they
-    // are no longer in the composed tree.
-    for (nsIContent* child = olderShadow->GetFirstChild(); child;
-         child = child->GetNextSibling()) {
-      child->UnbindFromTree(true, false);
-    }
-
-    olderShadow->SetIsComposedDocParticipant(false);
-  }
 
   // xblBinding takes ownership of docInfo.
   RefPtr<nsXBLBinding> xblBinding = new nsXBLBinding(shadowRoot, protoBinding);
   shadowRoot->SetAssociatedBinding(xblBinding);
   xblBinding->SetBoundElement(this);
 
   SetXBLBinding(xblBinding);
   return shadowRoot.forget();

--- a/dom/base/FragmentOrElement.cpp
+++ b/dom/base/FragmentOrElement.cpp
@@ -1042,33 +1042,20 @@ nsIContent::GetEventTargetParent(EventCh
   }
 
   nsIContent* parent = GetParent();
 
   // Web components have a special event chain that need to account
   // for destination insertion points where nodes have been distributed.
   nsTArray<nsIContent*>* destPoints = GetExistingDestInsertionPoints();
   if (destPoints && !destPoints->IsEmpty()) {
-    // Push destination insertion points to aVisitor.mDestInsertionPoints
-    // excluding shadow insertion points.
-    bool didPushNonShadowInsertionPoint = false;
+    // Push destination insertion points to aVisitor.mDestInsertionPoints.
     for (uint32_t i = 0; i < destPoints->Length(); i++) {
       nsIContent* point = destPoints->ElementAt(i);
-      if (!ShadowRoot::IsShadowInsertionPoint(point)) {
-        aVisitor.mDestInsertionPoints.AppendElement(point);
-        didPushNonShadowInsertionPoint = true;
-      }
-    }
-
-    // Next node in the event path is the final destination
-    // (non-shadow) insertion point that was pushed.
-    if (didPushNonShadowInsertionPoint) {
-      parent = aVisitor.mDestInsertionPoints.LastElement();
-      aVisitor.mDestInsertionPoints.SetLength(
-        aVisitor.mDestInsertionPoints.Length() - 1);
+      aVisitor.mDestInsertionPoints.AppendElement(point);
     }
   }
 
   ShadowRoot* thisShadowRoot = ShadowRoot::FromNode(this);
   if (thisShadowRoot) {
     if (!aVisitor.mEvent->mFlags.mComposed) {
       // If we do stop propagation, we still want to propagate
       // the event to chrome (nsPIDOMWindow::GetParentTarget()).
@@ -1082,20 +1069,17 @@ nsIContent::GetEventTargetParent(EventCh
       return NS_OK;
     }
 
     if (!aVisitor.mDestInsertionPoints.IsEmpty()) {
       parent = aVisitor.mDestInsertionPoints.LastElement();
       aVisitor.mDestInsertionPoints.SetLength(
         aVisitor.mDestInsertionPoints.Length() - 1);
     } else {
-      // The pool host for the youngest shadow root is shadow DOM host,
-      // for older shadow roots, it is the shadow insertion point
-      // where the shadow root is projected, nullptr if none exists.
-      parent = thisShadowRoot->GetPoolHost();
+      parent = thisShadowRoot->GetHost();
     }
   }
 
   // Event may need to be retargeted if this is the root of a native
   // anonymous content subtree or event is dispatched somewhere inside XBL.
   if (isAnonForEvents) {
 #ifdef DEBUG
     // If a DOM event is explicitly dispatched using node.dispatchEvent(), then
@@ -2614,13 +2598,12 @@ FragmentOrElement::SetIsElementInStyleSc
 }
 
 void
 FragmentOrElement::SetIsElementInStyleScopeFlagOnShadowTree(bool aInStyleScope)
 {
   NS_ASSERTION(IsElement(), "calling SetIsElementInStyleScopeFlagOnShadowTree "
                             "on a non-Element is useless");
   ShadowRoot* shadowRoot = GetShadowRoot();
-  while (shadowRoot) {
+  if (shadowRoot) {
     shadowRoot->SetIsElementInStyleScopeFlagOnSubtree(aInStyleScope);
-    shadowRoot = shadowRoot->GetOlderShadowRoot();
   }
 }

--- a/dom/base/ShadowRoot.cpp
+++ b/dom/base/ShadowRoot.cpp
@@ -10,99 +10,90 @@
 #include "mozilla/dom/DocumentFragment.h"
 #include "ChildIterator.h"
 #include "nsContentUtils.h"
 #include "nsDOMClassInfoID.h"
 #include "nsIDOMHTMLElement.h"
 #include "nsIStyleSheetLinkingElement.h"
 #include "mozilla/dom/Element.h"
 #include "mozilla/dom/HTMLContentElement.h"
-#include "mozilla/dom/HTMLShadowElement.h"
 #include "nsXBLPrototypeBinding.h"
 #include "mozilla/StyleSheet.h"
 #include "mozilla/StyleSheetInlines.h"
 
 using namespace mozilla;
 using namespace mozilla::dom;
 
 NS_IMPL_CYCLE_COLLECTION_CLASS(ShadowRoot)
 
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(ShadowRoot,
                                                   DocumentFragment)
-  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mPoolHost)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mStyleSheetList)
-  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mOlderShadow)
-  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mYoungerShadow)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mAssociatedBinding)
   for (auto iter = tmp->mIdentifierMap.ConstIter(); !iter.Done();
        iter.Next()) {
     iter.Get()->Traverse(&cb);
   }
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
 
-NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(ShadowRoot,
-                                                DocumentFragment)
-  if (tmp->mPoolHost) {
-    tmp->mPoolHost->RemoveMutationObserver(tmp);
+NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(ShadowRoot)
+  if (tmp->GetHost()) {
+    tmp->GetHost()->RemoveMutationObserver(tmp);
   }
-  NS_IMPL_CYCLE_COLLECTION_UNLINK(mPoolHost)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mStyleSheetList)
-  NS_IMPL_CYCLE_COLLECTION_UNLINK(mOlderShadow)
-  NS_IMPL_CYCLE_COLLECTION_UNLINK(mYoungerShadow)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mAssociatedBinding)
   tmp->mIdentifierMap.Clear();
-NS_IMPL_CYCLE_COLLECTION_UNLINK_END
+NS_IMPL_CYCLE_COLLECTION_UNLINK_END_INHERITED(DocumentFragment)
 
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(ShadowRoot)
   NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIContent)
   NS_INTERFACE_MAP_ENTRY(nsIMutationObserver)
 NS_INTERFACE_MAP_END_INHERITING(DocumentFragment)
 
 NS_IMPL_ADDREF_INHERITED(ShadowRoot, DocumentFragment)
 NS_IMPL_RELEASE_INHERITED(ShadowRoot, DocumentFragment)
 
 ShadowRoot::ShadowRoot(Element* aElement,
                        already_AddRefed<mozilla::dom::NodeInfo>&& aNodeInfo,
                        nsXBLPrototypeBinding* aProtoBinding)
-  : DocumentFragment(aNodeInfo), mPoolHost(aElement),
-    mProtoBinding(aProtoBinding), mShadowElement(nullptr),
-    mInsertionPointChanged(false), mIsComposedDocParticipant(false)
+  : DocumentFragment(aNodeInfo)
+  , mProtoBinding(aProtoBinding)
+  , mInsertionPointChanged(false)
+  , mIsComposedDocParticipant(false)
 {
   SetHost(aElement);
 
   // Nodes in a shadow tree should never store a value
   // in the subtree root pointer, nodes in the shadow tree
   // track the subtree root using GetContainingShadow().
   ClearSubtreeRootPointer();
 
   SetFlags(NODE_IS_IN_SHADOW_TREE);
 
   ExtendedDOMSlots()->mBindingParent = aElement;
   ExtendedDOMSlots()->mContainingShadow = this;
 
   // Add the ShadowRoot as a mutation observer on the host to watch
   // for mutations because the insertion points in this ShadowRoot
   // may need to be updated when the host children are modified.
-  mPoolHost->AddMutationObserver(this);
+  GetHost()->AddMutationObserver(this);
 }
 
 ShadowRoot::~ShadowRoot()
 {
-  if (mPoolHost) {
+  if (GetHost()) {
     // mPoolHost may have been unlinked or a new ShadowRoot may have been
     // creating, making this one obsolete.
-    mPoolHost->RemoveMutationObserver(this);
+    GetHost()->RemoveMutationObserver(this);
   }
 
   UnsetFlags(NODE_IS_IN_SHADOW_TREE);
 
   // nsINode destructor expects mSubtreeRoot == this.
   SetSubtreeRootPointer(this);
-
-  SetHost(nullptr);
 }
 
 JSObject*
 ShadowRoot::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto)
 {
   return mozilla::dom::ShadowRootBinding::Wrap(aCx, this, aGivenProto);
 }
 
@@ -239,25 +230,16 @@ ShadowRoot::AddInsertionPoint(HTMLConten
 
 void
 ShadowRoot::RemoveInsertionPoint(HTMLContentElement* aInsertionPoint)
 {
   mInsertionPoints.RemoveElement(aInsertionPoint);
 }
 
 void
-ShadowRoot::SetYoungerShadow(ShadowRoot* aYoungerShadow)
-{
-  mYoungerShadow = aYoungerShadow;
-  mYoungerShadow->mOlderShadow = this;
-
-  ChangePoolHost(mYoungerShadow->GetShadowElement());
-}
-
-void
 ShadowRoot::RemoveDestInsertionPoint(nsIContent* aInsertionPoint,
                                      nsTArray<nsIContent*>& aDestInsertionPoints)
 {
   // Remove the insertion point from the destination insertion points.
   // Also remove all succeeding insertion points because it is no longer
   // possible for the content to be distributed into deeper node trees.
   int32_t index = aDestInsertionPoints.IndexOf(aInsertionPoint);
 
@@ -295,18 +277,17 @@ ShadowRoot::DistributeSingleNode(nsICont
   }
 
   // Find the index into the insertion point.
   if (insertionPoint) {
     nsCOMArray<nsIContent>& matchedNodes = insertionPoint->MatchedNodes();
     // Find the appropriate position in the matched node list for the
     // newly distributed content.
     bool isIndexFound = false;
-    MOZ_ASSERT(mPoolHost, "Where did the content come from if there is no pool host?");
-    ExplicitChildIterator childIterator(mPoolHost);
+    ExplicitChildIterator childIterator(GetHost());
     for (uint32_t i = 0; i < matchedNodes.Length(); i++) {
       // Seek through the host's explicit children until the inserted content
       // is found or when the current matched node is reached.
       if (childIterator.Seek(aContent, matchedNodes[i])) {
         // aContent was found before the current matched node.
         insertionPoint->InsertMatchedNode(i, aContent);
         isIndexFound = true;
         break;
@@ -316,42 +297,23 @@ ShadowRoot::DistributeSingleNode(nsICont
     if (!isIndexFound) {
       // We have still not found an index in the insertion point,
       // thus it must be at the end.
       MOZ_ASSERT(childIterator.Seek(aContent, nullptr),
                  "Trying to match a node that is not a candidate to be matched");
       insertionPoint->AppendMatchedNode(aContent);
     }
 
-    // Handle the case where the parent of the insertion point is a ShadowRoot
-    // that is projected into the younger ShadowRoot's shadow insertion point.
-    // The node distributed into the insertion point must be reprojected
-    // to the shadow insertion point.
-    if (insertionPoint->GetParent() == this &&
-        mYoungerShadow && mYoungerShadow->GetShadowElement()) {
-      mYoungerShadow->GetShadowElement()->DistributeSingleNode(aContent);
-    }
-
     // Handle the case where the parent of the insertion point has a ShadowRoot.
     // The node distributed into the insertion point must be reprojected to the
     // insertion points of the parent's ShadowRoot.
     ShadowRoot* parentShadow = insertionPoint->GetParent()->GetShadowRoot();
     if (parentShadow) {
       parentShadow->DistributeSingleNode(aContent);
     }
-
-    // Handle the case where the parent of the insertion point is the <shadow>
-    // element. The node distributed into the insertion point must be reprojected
-    // into the older ShadowRoot's insertion points.
-    if (mShadowElement && mShadowElement == insertionPoint->GetParent()) {
-      ShadowRoot* olderShadow = mShadowElement->GetOlderShadowRoot();
-      if (olderShadow) {
-        olderShadow->DistributeSingleNode(aContent);
-      }
-    }
   }
 }
 
 void
 ShadowRoot::RemoveDistributedNode(nsIContent* aContent)
 {
   // Find insertion point containing the content and remove the node.
   for (uint32_t i = 0; i < mInsertionPoints.Length(); i++) {
@@ -363,63 +325,38 @@ ShadowRoot::RemoveDistributedNode(nsICon
         // Removing the matched node will cause fallback content to be
         // used instead. Give up optimization and distribute all nodes.
         DistributeAllNodes();
         return;
       }
 
       mInsertionPoints[i]->RemoveMatchedNode(aContent);
 
-      // Handle the case where the parent of the insertion point is a ShadowRoot
-      // that is projected into the younger ShadowRoot's shadow insertion point.
-      // The removed node needs to be removed from the shadow insertion point.
-      if (mInsertionPoints[i]->GetParent() == this) {
-        if (mYoungerShadow && mYoungerShadow->GetShadowElement()) {
-          mYoungerShadow->GetShadowElement()->RemoveDistributedNode(aContent);
-        }
-      }
-
       // Handle the case where the parent of the insertion point has a ShadowRoot.
       // The removed node needs to be removed from the insertion points of the
       // parent's ShadowRoot.
       ShadowRoot* parentShadow = mInsertionPoints[i]->GetParent()->GetShadowRoot();
       if (parentShadow) {
         parentShadow->RemoveDistributedNode(aContent);
       }
 
-      // Handle the case where the parent of the insertion point is the <shadow>
-      // element. The removed node must be removed from the older ShadowRoot's
-      // insertion points.
-      if (mShadowElement && mShadowElement == mInsertionPoints[i]->GetParent()) {
-        ShadowRoot* olderShadow = mShadowElement->GetOlderShadowRoot();
-        if (olderShadow) {
-          olderShadow->RemoveDistributedNode(aContent);
-        }
-      }
-
       break;
     }
   }
 }
 
 void
 ShadowRoot::DistributeAllNodes()
 {
   // Create node pool.
   nsTArray<nsIContent*> nodePool;
-
-  // Make sure there is a pool host, an older shadow may not have
-  // one if the younger shadow does not have a <shadow> element.
-  if (mPoolHost) {
-    ExplicitChildIterator childIterator(mPoolHost);
-    for (nsIContent* content = childIterator.GetNextChild();
-         content;
-         content = childIterator.GetNextChild()) {
-      nodePool.AppendElement(content);
-    }
+  ExplicitChildIterator childIterator(GetHost());
+  for (nsIContent* content = childIterator.GetNextChild(); content;
+       content = childIterator.GetNextChild()) {
+    nodePool.AppendElement(content);
   }
 
   nsTArray<ShadowRoot*> shadowsToUpdate;
 
   for (uint32_t i = 0; i < mInsertionPoints.Length(); i++) {
     mInsertionPoints[i]->ClearMatchedNodes();
     // Assign matching nodes from node pool.
     for (uint32_t j = 0; j < nodePool.Length(); j++) {
@@ -440,30 +377,16 @@ ShadowRoot::DistributeAllNodes()
     // to the insertion point must be reprojected to the insertion points of the
     // parent's ShadowRoot.
     ShadowRoot* parentShadow = insertionParent->GetShadowRoot();
     if (parentShadow && !shadowsToUpdate.Contains(parentShadow)) {
       shadowsToUpdate.AppendElement(parentShadow);
     }
   }
 
-  // If there is a shadow insertion point in this ShadowRoot, the children
-  // of the shadow insertion point needs to be distributed into the insertion
-  // points of the older ShadowRoot.
-  if (mShadowElement && mOlderShadow) {
-    mOlderShadow->DistributeAllNodes();
-  }
-
-  // If there is a younger ShadowRoot with a shadow insertion point,
-  // then the children of this ShadowRoot needs to be distributed to
-  // the younger ShadowRoot's shadow insertion point.
-  if (mYoungerShadow && mYoungerShadow->GetShadowElement()) {
-    mYoungerShadow->GetShadowElement()->DistributeAllNodes();
-  }
-
   for (uint32_t i = 0; i < shadowsToUpdate.Length(); i++) {
     shadowsToUpdate[i]->DistributeAllNodes();
   }
 }
 
 void
 ShadowRoot::GetInnerHTML(nsAString& aInnerHTML)
 {
@@ -510,81 +433,27 @@ ShadowRoot::StyleSheets()
 {
   if (!mStyleSheetList) {
     mStyleSheetList = new ShadowRootStyleSheetList(this);
   }
 
   return mStyleSheetList;
 }
 
-void
-ShadowRoot::SetShadowElement(HTMLShadowElement* aShadowElement)
-{
-  // If there is already a shadow element point, remove
-  // the projected shadow because it is no longer an insertion
-  // point.
-  if (mShadowElement) {
-    mShadowElement->SetProjectedShadow(nullptr);
-  }
-
-  if (mOlderShadow) {
-    // Nodes for distribution will come from the new shadow element.
-    mOlderShadow->ChangePoolHost(aShadowElement);
-  }
-
-  // Set the new shadow element to project the older ShadowRoot because
-  // it is the current shadow insertion point.
-  mShadowElement = aShadowElement;
-  if (mShadowElement) {
-    mShadowElement->SetProjectedShadow(mOlderShadow);
-  }
-}
-
-void
-ShadowRoot::ChangePoolHost(nsIContent* aNewHost)
-{
-  if (mPoolHost) {
-    mPoolHost->RemoveMutationObserver(this);
-  }
-
-  // Clear the nodes matched to content insertion points
-  // because it is no longer relevant.
-  for (uint32_t i = 0; i < mInsertionPoints.Length(); i++) {
-    mInsertionPoints[i]->ClearMatchedNodes();
-  }
-
-  mPoolHost = aNewHost;
-  if (mPoolHost) {
-    mPoolHost->AddMutationObserver(this);
-  }
-}
-
-bool
-ShadowRoot::IsShadowInsertionPoint(nsIContent* aContent)
-{
-  if (!aContent) {
-    return false;
-  }
-
-  HTMLShadowElement* shadowElem = HTMLShadowElement::FromContent(aContent);
-  return shadowElem && shadowElem->IsInsertionPoint();
-}
-
 /**
  * Returns whether the web components pool population algorithm
  * on the host would contain |aContent|. This function ignores
  * insertion points in the pool, thus should only be used to
  * test nodes that have not yet been distributed.
  */
 bool
 ShadowRoot::IsPooledNode(nsIContent* aContent, nsIContent* aContainer,
                          nsIContent* aHost)
 {
-  if (nsContentUtils::IsContentInsertionPoint(aContent) ||
-      IsShadowInsertionPoint(aContent)) {
+  if (nsContentUtils::IsContentInsertionPoint(aContent)) {
     // Insertion points never end up in the pool.
     return false;
   }
 
   if (aContainer == aHost &&
       nsContentUtils::IsInSameAnonymousTree(aContainer, aContent)) {
     // Children of the host will end up in the pool. We check to ensure
     // that the content is in the same anonymous tree as the container
@@ -607,17 +476,17 @@ ShadowRoot::IsPooledNode(nsIContent* aCo
 void
 ShadowRoot::AttributeChanged(nsIDocument* aDocument,
                              Element* aElement,
                              int32_t aNameSpaceID,
                              nsIAtom* aAttribute,
                              int32_t aModType,
                              const nsAttrValue* aOldValue)
 {
-  if (!IsPooledNode(aElement, aElement->GetParent(), mPoolHost)) {
+  if (!IsPooledNode(aElement, aElement->GetParent(), GetHost())) {
     return;
   }
 
   // Attributes may change insertion point matching, find its new distribution.
   RemoveDistributedNode(aElement);
   DistributeSingleNode(aElement);
 }
 
@@ -640,17 +509,17 @@ ShadowRoot::ContentAppended(nsIDocument*
     // Add insertion point to destination insertion points of fallback content.
     if (nsContentUtils::IsContentInsertionPoint(aContainer)) {
       HTMLContentElement* content = HTMLContentElement::FromContent(aContainer);
       if (content->MatchedNodes().IsEmpty()) {
         currentChild->DestInsertionPoints().AppendElement(aContainer);
       }
     }
 
-    if (IsPooledNode(currentChild, aContainer, mPoolHost)) {
+    if (IsPooledNode(currentChild, aContainer, GetHost())) {
       DistributeSingleNode(currentChild);
     }
 
     currentChild = currentChild->GetNextSibling();
   }
 }
 
 void
@@ -662,17 +531,17 @@ ShadowRoot::ContentInserted(nsIDocument*
   if (mInsertionPointChanged) {
     DistributeAllNodes();
     mInsertionPointChanged = false;
     return;
   }
 
   // Watch for new nodes added to the pool because the node
   // may need to be added to an insertion point.
-  if (IsPooledNode(aChild, aContainer, mPoolHost)) {
+  if (IsPooledNode(aChild, aContainer, GetHost())) {
     // Add insertion point to destination insertion points of fallback content.
     if (nsContentUtils::IsContentInsertionPoint(aContainer)) {
       HTMLContentElement* content = HTMLContentElement::FromContent(aContainer);
       if (content->MatchedNodes().IsEmpty()) {
         aChild->DestInsertionPoints().AppendElement(aContainer);
       }
     }
 
@@ -699,38 +568,29 @@ ShadowRoot::ContentRemoved(nsIDocument* 
     HTMLContentElement* content = HTMLContentElement::FromContent(aContainer);
     if (content->MatchedNodes().IsEmpty()) {
       aChild->DestInsertionPoints().Clear();
     }
   }
 
   // Watch for node that is removed from the pool because
   // it may need to be removed from an insertion point.
-  if (IsPooledNode(aChild, aContainer, mPoolHost)) {
+  if (IsPooledNode(aChild, aContainer, GetHost())) {
     RemoveDistributedNode(aChild);
   }
 }
 
 nsresult
 ShadowRoot::Clone(mozilla::dom::NodeInfo *aNodeInfo, nsINode **aResult,
                   bool aPreallocateChildren) const
 {
   *aResult = nullptr;
   return NS_ERROR_DOM_DATA_CLONE_ERR;
 }
 
-void
-ShadowRoot::DestroyContent()
-{
-  if (mOlderShadow) {
-    mOlderShadow->DestroyContent();
-  }
-  DocumentFragment::DestroyContent();
-}
-
 NS_IMPL_CYCLE_COLLECTION_INHERITED(ShadowRootStyleSheetList, StyleSheetList,
                                    mShadowRoot)
 
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(ShadowRootStyleSheetList)
 NS_INTERFACE_MAP_END_INHERITING(StyleSheetList)
 
 NS_IMPL_ADDREF_INHERITED(ShadowRootStyleSheetList, StyleSheetList)
 NS_IMPL_RELEASE_INHERITED(ShadowRootStyleSheetList, StyleSheetList)

--- a/dom/base/ShadowRoot.h
+++ b/dom/base/ShadowRoot.h
@@ -20,61 +20,43 @@ class nsIAtom;
 class nsIContent;
 class nsXBLPrototypeBinding;
 
 namespace mozilla {
 namespace dom {
 
 class Element;
 class HTMLContentElement;
-class HTMLShadowElement;
 class ShadowRootStyleSheetList;
 
 class ShadowRoot final : public DocumentFragment,
                          public nsStubMutationObserver
 {
   friend class ShadowRootStyleSheetList;
 public:
   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(ShadowRoot,
                                            DocumentFragment)
   NS_DECL_ISUPPORTS_INHERITED
 
   NS_DECL_NSIMUTATIONOBSERVER_ATTRIBUTECHANGED
   NS_DECL_NSIMUTATIONOBSERVER_CONTENTAPPENDED
   NS_DECL_NSIMUTATIONOBSERVER_CONTENTINSERTED
   NS_DECL_NSIMUTATIONOBSERVER_CONTENTREMOVED
 
-  ShadowRoot(Element* aElement, already_AddRefed<mozilla::dom::NodeInfo>&& aNodeInfo,
+  ShadowRoot(Element* aElement,
+             already_AddRefed<mozilla::dom::NodeInfo>&& aNodeInfo,
              nsXBLPrototypeBinding* aProtoBinding);
 
   void AddToIdTable(Element* aElement, nsIAtom* aId);
   void RemoveFromIdTable(Element* aElement, nsIAtom* aId);
   void InsertSheet(StyleSheet* aSheet, nsIContent* aLinkingContent);
   void RemoveSheet(StyleSheet* aSheet);
   bool ApplyAuthorStyles();
   void SetApplyAuthorStyles(bool aApplyAuthorStyles);
   StyleSheetList* StyleSheets();
-  HTMLShadowElement* GetShadowElement() { return mShadowElement; }
-
-  /**
-   * Sets the current shadow insertion point where the older
-   * ShadowRoot will be projected.
-   */
-  void SetShadowElement(HTMLShadowElement* aShadowElement);
-
-  /**
-   * Change the node that populates the distribution pool with
-   * its children. This is distinct from the ShadowRoot host described
-   * in the specifications. The ShadowRoot host is the element
-   * which created this ShadowRoot and does not change. The pool host
-   * is the same as the ShadowRoot host if this is the youngest
-   * ShadowRoot. If this is an older ShadowRoot, the pool host is
-   * the <shadow> element in the younger ShadowRoot (if it exists).
-   */
-  void ChangePoolHost(nsIContent* aNewHost);
 
   /**
    * Distributes a single explicit child of the pool host to the content
    * insertion points in this ShadowRoot.
    */
   void DistributeSingleNode(nsIContent* aContent);
 
   /**
@@ -87,98 +69,69 @@ public:
    * Distributes all the explicit children of the pool host to the content
    * insertion points in this ShadowRoot.
    */
   void DistributeAllNodes();
 
   void AddInsertionPoint(HTMLContentElement* aInsertionPoint);
   void RemoveInsertionPoint(HTMLContentElement* aInsertionPoint);
 
-  void SetYoungerShadow(ShadowRoot* aYoungerShadow);
-  ShadowRoot* GetYoungerShadowRoot() { return mYoungerShadow; }
   void SetInsertionPointChanged() { mInsertionPointChanged = true; }
 
   void SetAssociatedBinding(nsXBLBinding* aBinding) { mAssociatedBinding = aBinding; }
 
-  nsISupports* GetParentObject() const { return mPoolHost; }
-
-  nsIContent* GetPoolHost() { return mPoolHost; }
-  nsTArray<HTMLShadowElement*>& ShadowDescendants() { return mShadowDescendants; }
-
   JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;
 
   static bool IsPooledNode(nsIContent* aChild, nsIContent* aContainer,
                            nsIContent* aHost);
   static ShadowRoot* FromNode(nsINode* aNode);
-  static bool IsShadowInsertionPoint(nsIContent* aContent);
 
   static void RemoveDestInsertionPoint(nsIContent* aInsertionPoint,
                                        nsTArray<nsIContent*>& aDestInsertionPoints);
 
   // WebIDL methods.
   Element* GetElementById(const nsAString& aElementId);
   already_AddRefed<nsContentList>
     GetElementsByTagName(const nsAString& aNamespaceURI);
   already_AddRefed<nsContentList>
     GetElementsByTagNameNS(const nsAString& aNamespaceURI,
                            const nsAString& aLocalName);
   already_AddRefed<nsContentList>
     GetElementsByClassName(const nsAString& aClasses);
   void GetInnerHTML(nsAString& aInnerHTML);
   void SetInnerHTML(const nsAString& aInnerHTML, ErrorResult& aError);
   Element* Host();
-  ShadowRoot* GetOlderShadowRoot() { return mOlderShadow; }
   void StyleSheetChanged();
 
   bool IsComposedDocParticipant() { return mIsComposedDocParticipant; }
   void SetIsComposedDocParticipant(bool aIsComposedDocParticipant)
   {
     mIsComposedDocParticipant = aIsComposedDocParticipant;
   }
 
-  virtual void DestroyContent() override;
 protected:
   virtual ~ShadowRoot();
 
-  // The pool host is the parent of the nodes that will be distributed
-  // into the insertion points in this ShadowRoot. See |ChangeShadowRoot|.
-  nsCOMPtr<nsIContent> mPoolHost;
-
   // An array of content insertion points that are a descendant of the ShadowRoot
   // sorted in tree order. Insertion points are responsible for notifying
   // the ShadowRoot when they are removed or added as a descendant. The insertion
   // points are kept alive by the parent node, thus weak references are held
   // by the array.
   nsTArray<HTMLContentElement*> mInsertionPoints;
 
-  // An array of the <shadow> elements that are descendant of the ShadowRoot
-  // sorted in tree order. Only the first may be a shadow insertion point.
-  nsTArray<HTMLShadowElement*> mShadowDescendants;
-
   nsTHashtable<nsIdentifierMapEntry> mIdentifierMap;
   nsXBLPrototypeBinding* mProtoBinding;
 
   // It is necessary to hold a reference to the associated nsXBLBinding
   // because the binding holds a reference on the nsXBLDocumentInfo that
   // owns |mProtoBinding|.
   RefPtr<nsXBLBinding> mAssociatedBinding;
 
   RefPtr<ShadowRootStyleSheetList> mStyleSheetList;
 
-  // The current shadow insertion point of this ShadowRoot.
-  HTMLShadowElement* mShadowElement;
-
-  // The ShadowRoot that was created by the host element before
-  // this ShadowRoot was created.
-  RefPtr<ShadowRoot> mOlderShadow;
-
-  // The ShadowRoot that was created by the host element after
-  // this ShadowRoot was created.
-  RefPtr<ShadowRoot> mYoungerShadow;
-
   // A boolean that indicates that an insertion point was added or removed
   // from this ShadowRoot and that the nodes need to be redistributed into
   // the insertion points. After this flag is set, nodes will be distributed
   // on the next mutation event.
   bool mInsertionPointChanged;
 
   // Flag to indicate whether the descendants of this shadow root are part of the
   // composed document. Ideally, we would use a node flag on nodes to

--- a/dom/base/nsContentUtils.cpp
+++ b/dom/base/nsContentUtils.cpp
@@ -45,17 +45,16 @@
 #include "mozilla/dom/DOMTypes.h"
 #include "mozilla/dom/Element.h"
 #include "mozilla/dom/ElementInlines.h"
 #include "mozilla/dom/FileSystemSecurity.h"
 #include "mozilla/dom/FileBlobImpl.h"
 #include "mozilla/dom/HTMLInputElement.h"
 #include "mozilla/dom/HTMLTemplateElement.h"
 #include "mozilla/dom/HTMLContentElement.h"
-#include "mozilla/dom/HTMLShadowElement.h"
 #include "mozilla/dom/IPCBlobUtils.h"
 #include "mozilla/dom/Promise.h"
 #include "mozilla/dom/ScriptSettings.h"
 #include "mozilla/dom/TabParent.h"
 #include "mozilla/dom/TouchEvent.h"
 #include "mozilla/dom/ShadowRoot.h"
 #include "mozilla/dom/XULCommandEvent.h"
 #include "mozilla/dom/WorkerPrivate.h"
@@ -7562,30 +7561,16 @@ nsContentUtils::HasDistributedChildren(n
   }
 
   if (aContent->GetShadowRoot()) {
     // Children of a shadow root host are distributed
     // to content insertion points in the shadow root.
     return true;
   }
 
-  ShadowRoot* shadow = ShadowRoot::FromNode(aContent);
-  if (shadow) {
-    // Children of a shadow root are distributed to
-    // the shadow insertion point of the younger shadow root.
-    return shadow->GetYoungerShadowRoot();
-  }
-
-  HTMLShadowElement* shadowEl = HTMLShadowElement::FromContent(aContent);
-  if (shadowEl && shadowEl->IsInsertionPoint()) {
-    // Children of a shadow insertion points are distributed
-    // to the insertion points in the older shadow root.
-    return shadowEl->GetOlderShadowRoot();
-  }
-
   HTMLContentElement* contentEl = HTMLContentElement::FromContent(aContent);
   if (contentEl && contentEl->IsInsertionPoint()) {
     // Children of a content insertion point are distributed to the
     // content insertion point if the content insertion point does
     // not match any nodes (fallback content).
     return contentEl->MatchedNodes().IsEmpty();
   }
 

--- a/dom/base/nsGkAtomList.h
+++ b/dom/base/nsGkAtomList.h
@@ -1655,17 +1655,16 @@ GK_ATOM(requiredExtensions, "requiredExt
 GK_ATOM(requiredFeatures, "requiredFeatures")
 GK_ATOM(rotate, "rotate")
 GK_ATOM(rx, "rx")
 GK_ATOM(ry, "ry")
 GK_ATOM(saturate, "saturate")
 GK_ATOM(saturation, "saturation")
 GK_ATOM(set, "set")
 GK_ATOM(seed, "seed")
-GK_ATOM(shadow, "shadow")
 GK_ATOM(shape_rendering, "shape-rendering")
 GK_ATOM(skewX, "skewX")
 GK_ATOM(skewY, "skewY")
 GK_ATOM(slope, "slope")
 GK_ATOM(softLight, "soft-light")
 GK_ATOM(spacing, "spacing")
 GK_ATOM(spacingAndGlyphs, "spacingAndGlyphs")
 GK_ATOM(specularConstant, "specularConstant")

--- a/dom/base/nsNodeUtils.cpp
+++ b/dom/base/nsNodeUtils.cpp
@@ -61,17 +61,17 @@ using mozilla::AutoJSContext;
       /* No need to explicitly notify the first observer first    \
          since that'll happen anyway. */                          \
       NS_OBSERVER_AUTO_ARRAY_NOTIFY_OBSERVERS(                    \
         slots->mMutationObservers, nsIMutationObserver, 1,        \
         func_, params_);                                          \
     }                                                             \
     ShadowRoot* shadow = ShadowRoot::FromNode(node);              \
     if (shadow) {                                                 \
-      node = shadow->GetPoolHost();                               \
+      node = shadow->GetHost();                                   \
     } else {                                                      \
       node = node->GetParentNode();                               \
     }                                                             \
   } while (node);                                                 \
   if (needsEnterLeave) {                                          \
     nsDOMMutationObserver::LeaveMutationHandling();               \
   }                                                               \
   PR_END_MACRO
@@ -89,17 +89,17 @@ using mozilla::AutoJSContext;
       /* No need to explicitly notify the first observer first    \
          since that'll happen anyway. */                          \
       NS_OBSERVER_AUTO_ARRAY_NOTIFY_OBSERVERS_WITH_QI(            \
         slots->mMutationObservers, nsIMutationObserver, 1,        \
         nsIAnimationObserver, func_, params_);                    \
     }                                                             \
     ShadowRoot* shadow = ShadowRoot::FromNode(node);              \
     if (shadow) {                                                 \
-      node = shadow->GetPoolHost();                               \
+      node = shadow->GetHost();                                   \
     } else {                                                      \
       node = node->GetParentNode();                               \
     }                                                             \
   } while (node);                                                 \
   if (needsEnterLeave) {                                          \
     nsDOMMutationObserver::LeaveMutationHandling();               \
   }                                                               \
   PR_END_MACRO

--- a/dom/base/test/test_mutationobservers.html
+++ b/dom/base/test/test_mutationobservers.html
@@ -582,58 +582,32 @@ function testOutsideShadowDOM() {
          "because createShadowRoot is not supported");
     then(testMarquee);
     return;
   }
   var m = new M(function(records, observer) {
     is(records.length, 1);
     is(records[0].type, "attributes", "Should have got attributes");
     observer.disconnect();
-    then(testInsideShadowDOM);
+    then(testMarquee);
   });
   m.observe(div, {
       attributes: true,
       childList: true,
       characterData: true,
       subtree: true
     })
   var sr = div.createShadowRoot();
   sr.innerHTML = "<div" + ">text</" + "div>";
   sr.firstChild.setAttribute("foo", "bar");
   sr.firstChild.firstChild.data = "text2";
   sr.firstChild.appendChild(document.createElement("div"));
   div.setAttribute("foo", "bar");
 }
 
-function testInsideShadowDOM() {
-  var m = new M(function(records, observer) {
-    is(records.length, 4);
-    is(records[0].type, "childList");
-    is(records[1].type, "attributes");
-    is(records[2].type, "characterData");
-    is(records[3].type, "childList");
-    observer.disconnect();
-    then(testMarquee);
-  });
-  var sr = div.createShadowRoot();
-  m.observe(sr, {
-      attributes: true,
-      childList: true,
-      characterData: true,
-      subtree: true
-    });
-
-  sr.innerHTML = "<div" + ">text</" + "div>";
-  sr.firstChild.setAttribute("foo", "bar");
-  sr.firstChild.firstChild.data = "text2";
-  sr.firstChild.appendChild(document.createElement("div"));
-  div.setAttribute("foo", "bar2");
-
-}
-
 function testMarquee() {
   var m = new M(function(records, observer) {
     is(records.length, 1);
     is(records[0].type, "attributes");
     is(records[0].attributeName, "ok");
     is(records[0].oldValue, null);
     observer.disconnect();
     then(testStyleCreate);

deleted file mode 100644
--- a/dom/html/HTMLShadowElement.cpp
+++ /dev/null
@@ -1,373 +0,0 @@
-/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/* vim: set ts=8 sts=2 et sw=2 tw=80: */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-#include "mozilla/dom/ShadowRoot.h"
-
-#include "ChildIterator.h"
-#include "nsContentUtils.h"
-#include "nsDocument.h"
-#include "mozilla/dom/HTMLShadowElement.h"
-#include "mozilla/dom/HTMLUnknownElement.h"
-#include "mozilla/dom/HTMLShadowElementBinding.h"
-
-// Expand NS_IMPL_NS_NEW_HTML_ELEMENT(Shadow) to add check for web components
-// being enabled.
-nsGenericHTMLElement*
-NS_NewHTMLShadowElement(already_AddRefed<mozilla::dom::NodeInfo>&& aNodeInfo,
-                        mozilla::dom::FromParser aFromParser)
-{
-  // When this check is removed, remove the nsDocument.h and
-  // HTMLUnknownElement.h includes.  Also remove nsINode::IsHTMLShadowElement.
-  //
-  // We have to jump through some hoops to be able to produce both NodeInfo* and
-  // already_AddRefed<NodeInfo>& for our callees.
-  RefPtr<mozilla::dom::NodeInfo> nodeInfo(aNodeInfo);
-  if (!nsDocument::IsWebComponentsEnabled(nodeInfo)) {
-    already_AddRefed<mozilla::dom::NodeInfo> nodeInfoArg(nodeInfo.forget());
-    return new mozilla::dom::HTMLUnknownElement(nodeInfoArg);
-  }
-
-  already_AddRefed<mozilla::dom::NodeInfo> nodeInfoArg(nodeInfo.forget());
-  return new mozilla::dom::HTMLShadowElement(nodeInfoArg);
-}
-
-using namespace mozilla::dom;
-
-HTMLShadowElement::HTMLShadowElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
-  : nsGenericHTMLElement(aNodeInfo), mIsInsertionPoint(false)
-{
-}
-
-HTMLShadowElement::~HTMLShadowElement()
-{
-  if (mProjectedShadow) {
-    mProjectedShadow->RemoveMutationObserver(this);
-  }
-}
-
-NS_IMPL_CYCLE_COLLECTION_CLASS(HTMLShadowElement)
-
-NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(HTMLShadowElement,
-                                                  nsGenericHTMLElement)
-  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mProjectedShadow)
-NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
-
-NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(HTMLShadowElement,
-                                                nsGenericHTMLElement)
-  if (tmp->mProjectedShadow) {
-    tmp->mProjectedShadow->RemoveMutationObserver(tmp);
-    tmp->mProjectedShadow = nullptr;
-  }
-NS_IMPL_CYCLE_COLLECTION_UNLINK_END
-
-NS_IMPL_ADDREF_INHERITED(HTMLShadowElement, Element)
-NS_IMPL_RELEASE_INHERITED(HTMLShadowElement, Element)
-
-NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(HTMLShadowElement)
-NS_INTERFACE_MAP_END_INHERITING(nsGenericHTMLElement)
-
-NS_IMPL_ELEMENT_CLONE(HTMLShadowElement)
-
-JSObject*
-HTMLShadowElement::WrapNode(JSContext *aCx, JS::Handle<JSObject*> aGivenProto)
-{
-  return HTMLShadowElementBinding::Wrap(aCx, this, aGivenProto);
-}
-
-void
-HTMLShadowElement::SetProjectedShadow(ShadowRoot* aProjectedShadow)
-{
-  if (mProjectedShadow) {
-    mProjectedShadow->RemoveMutationObserver(this);
-
-    // The currently projected ShadowRoot is going away,
-    // thus the destination insertion points need to be updated.
-    ExplicitChildIterator childIterator(mProjectedShadow);
-    for (nsIContent* content = childIterator.GetNextChild();
-         content;
-         content = childIterator.GetNextChild()) {
-      ShadowRoot::RemoveDestInsertionPoint(this, content->DestInsertionPoints());
-    }
-  }
-
-  mProjectedShadow = aProjectedShadow;
-  if (mProjectedShadow) {
-    // A new ShadowRoot is being projected, thus its explcit
-    // children will be distributed to this shadow insertion point.
-    ExplicitChildIterator childIterator(mProjectedShadow);
-    for (nsIContent* content = childIterator.GetNextChild();
-         content;
-         content = childIterator.GetNextChild()) {
-      content->DestInsertionPoints().AppendElement(this);
-    }
-
-    // Watch for mutations on the projected shadow because
-    // it affects the nodes that are distributed to this shadow
-    // insertion point.
-    mProjectedShadow->AddMutationObserver(this);
-  }
-}
-
-static bool
-IsInFallbackContent(nsIContent* aContent)
-{
-  nsINode* parentNode = aContent->GetParentNode();
-  while (parentNode) {
-    if (parentNode->IsHTMLElement(nsGkAtoms::content)) {
-      return true;
-    }
-    parentNode = parentNode->GetParentNode();
-  }
-
-  return false;
-}
-
-nsresult
-HTMLShadowElement::BindToTree(nsIDocument* aDocument,
-                              nsIContent* aParent,
-                              nsIContent* aBindingParent,
-                              bool aCompileEventHandlers)
-{
-  RefPtr<ShadowRoot> oldContainingShadow = GetContainingShadow();
-
-  nsresult rv = nsGenericHTMLElement::BindToTree(aDocument, aParent,
-                                                 aBindingParent,
-                                                 aCompileEventHandlers);
-  NS_ENSURE_SUCCESS(rv, rv);
-
-  ShadowRoot* containingShadow = GetContainingShadow();
-  if (containingShadow && !oldContainingShadow) {
-    // Keep track of all descendant <shadow> elements in tree order so
-    // that when the current shadow insertion point is removed, the next
-    // one can be found quickly.
-    TreeOrderComparator comparator;
-    containingShadow->ShadowDescendants().InsertElementSorted(this, comparator);
-
-    if (containingShadow->ShadowDescendants()[0] != this) {
-      // Only the first <shadow> (in tree order) of a ShadowRoot can be an insertion point.
-      return NS_OK;
-    }
-
-    if (IsInFallbackContent(this)) {
-      // If the first shadow element in tree order is invalid (in fallback content),
-      // the containing ShadowRoot will not have a shadow insertion point.
-      containingShadow->SetShadowElement(nullptr);
-    } else {
-      mIsInsertionPoint = true;
-      containingShadow->SetShadowElement(this);
-    }
-
-    containingShadow->SetInsertionPointChanged();
-  }
-
-  if (mIsInsertionPoint && containingShadow) {
-    // Propagate BindToTree calls to projected shadow root children.
-    ShadowRoot* projectedShadow = containingShadow->GetOlderShadowRoot();
-    if (projectedShadow) {
-      projectedShadow->SetIsComposedDocParticipant(IsInComposedDoc());
-
-      for (nsIContent* child = projectedShadow->GetFirstChild(); child;
-           child = child->GetNextSibling()) {
-        rv = child->BindToTree(nullptr, projectedShadow,
-                               projectedShadow->GetBindingParent(),
-                               aCompileEventHandlers);
-        NS_ENSURE_SUCCESS(rv, rv);
-      }
-    }
-  }
-
-  return NS_OK;
-}
-
-void
-HTMLShadowElement::UnbindFromTree(bool aDeep, bool aNullParent)
-{
-  RefPtr<ShadowRoot> oldContainingShadow = GetContainingShadow();
-
-  if (mIsInsertionPoint && oldContainingShadow) {
-    // Propagate UnbindFromTree call to previous projected shadow
-    // root children.
-    ShadowRoot* projectedShadow = oldContainingShadow->GetOlderShadowRoot();
-    if (projectedShadow) {
-      for (nsIContent* child = projectedShadow->GetFirstChild(); child;
-           child = child->GetNextSibling()) {
-        child->UnbindFromTree(true, false);
-      }
-
-      projectedShadow->SetIsComposedDocParticipant(false);
-    }
-  }
-
-  nsGenericHTMLElement::UnbindFromTree(aDeep, aNullParent);
-
-  if (oldContainingShadow && !GetContainingShadow() && mIsInsertionPoint) {
-    nsTArray<HTMLShadowElement*>& shadowDescendants =
-      oldContainingShadow->ShadowDescendants();
-    shadowDescendants.RemoveElement(this);
-    oldContainingShadow->SetShadowElement(nullptr);
-
-    // Find the next shadow insertion point.
-    if (shadowDescendants.Length() > 0 &&
-        !IsInFallbackContent(shadowDescendants[0])) {
-      oldContainingShadow->SetShadowElement(shadowDescendants[0]);
-    }
-
-    oldContainingShadow->SetInsertionPointChanged();
-
-    mIsInsertionPoint = false;
-  }
-}
-
-void
-HTMLShadowElement::DistributeSingleNode(nsIContent* aContent)
-{
-  if (aContent->DestInsertionPoints().Contains(this)) {
-    // Node has already been distrbuted this this node,
-    // we are done.
-    return;
-  }
-
-  aContent->DestInsertionPoints().AppendElement(this);
-
-  // Handle the case where the shadow element is a child of
-  // a node with a ShadowRoot. The nodes that have been distributed to
-  // this shadow insertion point will need to be reprojected into the
-  // insertion points of the parent's ShadowRoot.
-  ShadowRoot* parentShadowRoot = GetParent()->GetShadowRoot();
-  if (parentShadowRoot) {
-    parentShadowRoot->DistributeSingleNode(aContent);
-    return;
-  }
-
-  // Handle the case where the parent of this shadow element is a ShadowRoot
-  // that is projected into a shadow insertion point in the younger ShadowRoot.
-  ShadowRoot* containingShadow = GetContainingShadow();
-  ShadowRoot* youngerShadow = containingShadow->GetYoungerShadowRoot();
-  if (youngerShadow && GetParent() == containingShadow) {
-    HTMLShadowElement* youngerShadowElement = youngerShadow->GetShadowElement();
-    if (youngerShadowElement) {
-      youngerShadowElement->DistributeSingleNode(aContent);
-    }
-  }
-}
-
-void
-HTMLShadowElement::RemoveDistributedNode(nsIContent* aContent)
-{
-  ShadowRoot::RemoveDestInsertionPoint(this, aContent->DestInsertionPoints());
-
-  // Handle the case where the shadow element is a child of
-  // a node with a ShadowRoot. The nodes that have been distributed to
-  // this shadow insertion point will need to be removed from the
-  // insertion points of the parent's ShadowRoot.
-  ShadowRoot* parentShadowRoot = GetParent()->GetShadowRoot();
-  if (parentShadowRoot) {
-    parentShadowRoot->RemoveDistributedNode(aContent);
-    return;
-  }
-
-  // Handle the case where the parent of this shadow element is a ShadowRoot
-  // that is projected into a shadow insertion point in the younger ShadowRoot.
-  ShadowRoot* containingShadow = GetContainingShadow();
-  ShadowRoot* youngerShadow = containingShadow->GetYoungerShadowRoot();
-  if (youngerShadow && GetParent() == containingShadow) {
-    HTMLShadowElement* youngerShadowElement = youngerShadow->GetShadowElement();
-    if (youngerShadowElement) {
-      youngerShadowElement->RemoveDistributedNode(aContent);
-    }
-  }
-}
-
-void
-HTMLShadowElement::DistributeAllNodes()
-{
-  // All the explicit children of the projected ShadowRoot are distributed
-  // into this shadow insertion point so update the destination insertion
-  // points.
-  ShadowRoot* containingShadow = GetContainingShadow();
-  ShadowRoot* olderShadow = containingShadow->GetOlderShadowRoot();
-  if (olderShadow) {
-    ExplicitChildIterator childIterator(olderShadow);
-    for (nsIContent* content = childIterator.GetNextChild();
-         content;
-         content = childIterator.GetNextChild()) {
-      ShadowRoot::RemoveDestInsertionPoint(this, content->DestInsertionPoints());
-      content->DestInsertionPoints().AppendElement(this);
-    }
-  }
-
-  // Handle the case where the shadow element is a child of
-  // a node with a ShadowRoot. The nodes that have been distributed to
-  // this shadow insertion point will need to be reprojected into the
-  // insertion points of the parent's ShadowRoot.
-  ShadowRoot* parentShadowRoot = GetParent()->GetShadowRoot();
-  if (parentShadowRoot) {
-    parentShadowRoot->DistributeAllNodes();
-    return;
-  }
-
-  // Handle the case where the parent of this shadow element is a ShadowRoot
-  // that is projected into a shadow insertion point in the younger ShadowRoot.
-  ShadowRoot* youngerShadow = containingShadow->GetYoungerShadowRoot();
-  if (youngerShadow && GetParent() == containingShadow) {
-    HTMLShadowElement* youngerShadowElement = youngerShadow->GetShadowElement();
-    if (youngerShadowElement) {
-      youngerShadowElement->DistributeAllNodes();
-    }
-  }
-}
-
-void
-HTMLShadowElement::ContentAppended(nsIDocument* aDocument,
-                                   nsIContent* aContainer,
-                                   nsIContent* aFirstNewContent,
-                                   int32_t aNewIndexInContainer)
-{
-  // Watch for content appended to the projected shadow (the ShadowRoot that
-  // will be rendered in place of this shadow insertion point) because the
-  // nodes may need to be distributed into other insertion points.
-  nsIContent* currentChild = aFirstNewContent;
-  while (currentChild) {
-    if (ShadowRoot::IsPooledNode(currentChild, aContainer, mProjectedShadow)) {
-      DistributeSingleNode(currentChild);
-    }
-    currentChild = currentChild->GetNextSibling();
-  }
-}
-
-void
-HTMLShadowElement::ContentInserted(nsIDocument* aDocument,
-                                   nsIContent* aContainer,
-                                   nsIContent* aChild,
-                                   int32_t aIndexInContainer)
-{
-  // Watch for content appended to the projected shadow (the ShadowRoot that
-  // will be rendered in place of this shadow insertion point) because the
-  // nodes may need to be distributed into other insertion points.
-  if (!ShadowRoot::IsPooledNode(aChild, aContainer, mProjectedShadow)) {
-    return;
-  }
-
-  DistributeSingleNode(aChild);
-}
-
-void
-HTMLShadowElement::ContentRemoved(nsIDocument* aDocument,
-                                  nsIContent* aContainer,
-                                  nsIContent* aChild,
-                                  int32_t aIndexInContainer,
-                                  nsIContent* aPreviousSibling)
-{
-  // Watch for content removed from the projected shadow (the ShadowRoot that
-  // will be rendered in place of this shadow insertion point) because the
-  // nodes may need to be removed from other insertion points.
-  if (!ShadowRoot::IsPooledNode(aChild, aContainer, mProjectedShadow)) {
-    return;
-  }
-
-  RemoveDistributedNode(aChild);
-}
-

deleted file mode 100644
--- a/dom/html/HTMLShadowElement.h
+++ /dev/null
@@ -1,97 +0,0 @@
-/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/* vim: set ts=8 sts=2 et sw=2 tw=80: */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-#ifndef mozilla_dom_HTMLShadowElement_h__
-#define mozilla_dom_HTMLShadowElement_h__
-
-#include "nsGenericHTMLElement.h"
-
-namespace mozilla {
-namespace dom {
-
-class HTMLShadowElement final : public nsGenericHTMLElement,
-                                public nsStubMutationObserver
-{
-public:
-  explicit HTMLShadowElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo);
-
-  // nsISupports
-  NS_DECL_ISUPPORTS_INHERITED
-
-  NS_DECL_NSIMUTATIONOBSERVER_CONTENTAPPENDED
-  NS_DECL_NSIMUTATIONOBSERVER_CONTENTINSERTED
-  NS_DECL_NSIMUTATIONOBSERVER_CONTENTREMOVED
-
-  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(HTMLShadowElement,
-                                           nsGenericHTMLElement)
-
-  static HTMLShadowElement* FromContent(nsIContent* aContent)
-  {
-    if (aContent->IsHTMLShadowElement()) {
-      return static_cast<HTMLShadowElement*>(aContent);
-    }
-
-    return nullptr;
-  }
-
-  virtual bool IsHTMLShadowElement() const override { return true; }
-
-  virtual nsresult Clone(mozilla::dom::NodeInfo *aNodeInfo, nsINode **aResult,
-                         bool aPreallocateChildren) const override;
-
-  virtual nsresult BindToTree(nsIDocument* aDocument, nsIContent* aParent,
-                              nsIContent* aBindingParent,
-                              bool aCompileEventHandlers) override;
-
-  virtual void UnbindFromTree(bool aDeep = true,
-                              bool aNullParent = true) override;
-
-  bool IsInsertionPoint() { return mIsInsertionPoint; }
-
-  /**
-   * Sets the ShadowRoot that will be rendered in place of
-   * this shadow insertion point.
-   */
-  void SetProjectedShadow(ShadowRoot* aProjectedShadow);
-
-  /**
-   * Distributes a single explicit child of the projected ShadowRoot
-   * to relevant insertion points.
-   */
-  void DistributeSingleNode(nsIContent* aContent);
-
-  /**
-   * Removes a single explicit child of the projected ShadowRoot
-   * from relevant insertion points.
-   */
-  void RemoveDistributedNode(nsIContent* aContent);
-
-  /**
-   * Distributes all the explicit children of the projected ShadowRoot
-   * to the shadow insertion point in the younger ShadowRoot and
-   * the content insertion point of the parent node's ShadowRoot.
-   */
-  void DistributeAllNodes();
-
-  // WebIDL methods.
-  ShadowRoot* GetOlderShadowRoot() { return mProjectedShadow; }
-
-protected:
-  virtual ~HTMLShadowElement();
-
-  virtual JSObject* WrapNode(JSContext *aCx, JS::Handle<JSObject*> aGivenProto) override;
-
-  // The ShadowRoot that will be rendered in place of this shadow insertion point.
-  RefPtr<ShadowRoot> mProjectedShadow;
-
-  bool mIsInsertionPoint;
-};
-
-} // namespace dom
-} // namespace mozilla
-
-#endif // mozilla_dom_HTMLShadowElement_h__
-

--- a/dom/html/moz.build
+++ b/dom/html/moz.build
@@ -90,17 +90,16 @@ EXPORTS.mozilla.dom += [
     'HTMLOptionsCollection.h',
     'HTMLOutputElement.h',
     'HTMLParagraphElement.h',
     'HTMLPictureElement.h',
     'HTMLPreElement.h',
     'HTMLProgressElement.h',
     'HTMLScriptElement.h',
     'HTMLSelectElement.h',
-    'HTMLShadowElement.h',
     'HTMLSharedElement.h',
     'HTMLSharedListElement.h',
     'HTMLSourceElement.h',
     'HTMLSpanElement.h',
     'HTMLStyleElement.h',
     'HTMLSummaryElement.h',
     'HTMLTableCaptionElement.h',
     'HTMLTableCellElement.h',
@@ -170,17 +169,16 @@ UNIFIED_SOURCES += [
     'HTMLOptionsCollection.cpp',
     'HTMLOutputElement.cpp',
     'HTMLParagraphElement.cpp',
     'HTMLPictureElement.cpp',
     'HTMLPreElement.cpp',
     'HTMLProgressElement.cpp',
     'HTMLScriptElement.cpp',
     'HTMLSelectElement.cpp',
-    'HTMLShadowElement.cpp',
     'HTMLSharedElement.cpp',
     'HTMLSharedListElement.cpp',
     'HTMLSourceElement.cpp',
     'HTMLSpanElement.cpp',
     'HTMLStyleElement.cpp',
     'HTMLSummaryElement.cpp',
     'HTMLTableCaptionElement.cpp',
     'HTMLTableCellElement.cpp',

--- a/dom/html/nsGenericHTMLElement.h
+++ b/dom/html/nsGenericHTMLElement.h
@@ -1576,17 +1576,16 @@ NS_DECLARE_NS_NEW_HTML_ELEMENT(OptGroup)
 NS_DECLARE_NS_NEW_HTML_ELEMENT(Option)
 NS_DECLARE_NS_NEW_HTML_ELEMENT(Output)
 NS_DECLARE_NS_NEW_HTML_ELEMENT(Paragraph)
 NS_DECLARE_NS_NEW_HTML_ELEMENT(Picture)
 NS_DECLARE_NS_NEW_HTML_ELEMENT(Pre)
 NS_DECLARE_NS_NEW_HTML_ELEMENT(Progress)
 NS_DECLARE_NS_NEW_HTML_ELEMENT(Script)
 NS_DECLARE_NS_NEW_HTML_ELEMENT(Select)
-NS_DECLARE_NS_NEW_HTML_ELEMENT(Shadow)
 NS_DECLARE_NS_NEW_HTML_ELEMENT(Source)
 NS_DECLARE_NS_NEW_HTML_ELEMENT(Span)
 NS_DECLARE_NS_NEW_HTML_ELEMENT(Style)
 NS_DECLARE_NS_NEW_HTML_ELEMENT(Summary)
 NS_DECLARE_NS_NEW_HTML_ELEMENT(TableCaption)
 NS_DECLARE_NS_NEW_HTML_ELEMENT(TableCell)
 NS_DECLARE_NS_NEW_HTML_ELEMENT(TableCol)
 NS_DECLARE_NS_NEW_HTML_ELEMENT(Table)

--- a/dom/html/nsGenericHTMLFrameElement.cpp
+++ b/dom/html/nsGenericHTMLFrameElement.cpp
@@ -19,16 +19,17 @@
 #include "nsIInterfaceRequestorUtils.h"
 #include "nsIPermissionManager.h"
 #include "nsIPresShell.h"
 #include "nsIScrollable.h"
 #include "nsPresContext.h"
 #include "nsServiceManagerUtils.h"
 #include "nsSubDocumentFrame.h"
 #include "nsXULElement.h"
+#include "nsAttrValueOrString.h"
 
 using namespace mozilla;
 using namespace mozilla::dom;
 
 NS_IMPL_CYCLE_COLLECTION_CLASS(nsGenericHTMLFrameElement)
 
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(nsGenericHTMLFrameElement,
                                                   nsGenericHTMLElement)

--- a/dom/html/nsHTMLContentSink.cpp
+++ b/dom/html/nsHTMLContentSink.cpp
@@ -25,16 +25,17 @@
 #include "mozilla/dom/NodeInfo.h"
 #include "mozilla/dom/ScriptLoader.h"
 #include "nsIAppShell.h"
 #include "nsCRT.h"
 #include "prtime.h"
 #include "mozilla/Logging.h"
 #include "nsNodeUtils.h"
 #include "nsIContent.h"
+#include "mozilla/dom/CustomElementRegistry.h"
 #include "mozilla/dom/Element.h"
 #include "mozilla/Preferences.h"
 
 #include "nsGenericHTMLElement.h"
 
 #include "nsIDOMDocument.h"
 #include "nsIDOMDocumentType.h"
 #include "nsIScriptElement.h"

--- a/dom/tests/mochitest/general/test_interfaces.js
+++ b/dom/tests/mochitest/general/test_interfaces.js
@@ -509,18 +509,16 @@ var interfaceNamesInGlobalScope =
     "HTMLProgressElement",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "HTMLQuoteElement",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "HTMLScriptElement",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "HTMLSelectElement",
 // IMPORTANT: Do not change this list without review from a DOM peer!
-    {name: "HTMLShadowElement", stylo: false},
-// IMPORTANT: Do not change this list without review from a DOM peer!
     "HTMLSourceElement",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "HTMLSpanElement",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "HTMLStyleElement",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "HTMLTableCaptionElement",
 // IMPORTANT: Do not change this list without review from a DOM peer!

--- a/dom/tests/mochitest/webcomponents/mochitest.ini
+++ b/dom/tests/mochitest/webcomponents/mochitest.ini
@@ -28,18 +28,16 @@ skip-if = true || stylo # disabled - See
 [test_custom_element_upgrade.html]
 support-files =
   test_upgrade_page.html
   upgrade_tests.js
 [test_nested_content_element.html]
 skip-if = stylo # bug 1293844
 [test_dest_insertion_points.html]
 skip-if = stylo # bug 1293844
-[test_dest_insertion_points_shadow.html]
-skip-if = stylo # bug 1293844
 [test_fallback_dest_insertion_points.html]
 skip-if = stylo # bug 1293844
 [test_detached_style.html]
 skip-if = stylo # bug 1293844
 [test_dynamic_content_element_matching.html]
 skip-if = stylo # bug 1293844
 [test_document_adoptnode.html]
 skip-if = stylo # bug 1293844
@@ -48,37 +46,29 @@ skip-if = stylo # bug 1293844
 [test_document_register.html]
 [test_document_register_base_queue.html]
 [test_document_register_lifecycle.html]
 skip-if = true # disabled - See bug 1390396
 [test_document_register_parser.html]
 [test_document_register_stack.html]
 skip-if = true # disabled - See bug 1390396
 [test_document_shared_registry.html]
-[test_event_dispatch.html]
-skip-if = stylo # bug 1293844
 [test_event_retarget.html]
 skip-if = stylo # bug 1293844
 [test_event_stopping.html]
 skip-if = stylo # bug 1293844
 [test_template.html]
 [test_template_xhtml.html]
 [test_template_custom_elements.html]
 [test_shadowroot.html]
 skip-if = stylo # bug 1293844
 [test_shadowroot_inert_element.html]
 skip-if = stylo # bug 1293844
-[test_shadowroot_host.html]
-skip-if = stylo # bug 1293844
 [test_shadowroot_style.html]
 skip-if = stylo # bug 1293844
-[test_shadowroot_style_multiple_shadow.html]
-skip-if = stylo # bug 1293844
 [test_shadowroot_style_order.html]
 skip-if = stylo # bug 1293844
-[test_shadowroot_youngershadowroot.html]
-skip-if = stylo # bug 1293844
 [test_style_fallback_content.html]
 skip-if = stylo # bug 1293844
 [test_unresolved_pseudo_class.html]
 [test_link_prefetch.html]
 [test_bug1269155.html]
 skip-if = stylo # bug 1293844

deleted file mode 100644
--- a/dom/tests/mochitest/webcomponents/test_dest_insertion_points_shadow.html
+++ /dev/null
@@ -1,68 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<!--
-https://bugzilla.mozilla.org/show_bug.cgi?id=999999
--->
-<head>
-  <meta charset="utf-8">
-  <title>Test for Bug 999999</title>
-  <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
-  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
-</head>
-<body>
-<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=999999">Mozilla Bug 999999</a>
-<p id="display"></p>
-<div id="content">
-<div id="shadowhost"></div>
-</div>
-<pre id="test">
-</pre>
-<script type="application/javascript">
-
-/** Test for Bug 999999 **/
-var host = document.getElementById("shadowhost");
-
-// Test destination insertion points of node distributed to shadow element.
-var olderShadowRoot = host.createShadowRoot();
-var youngerShadowRoot = host.createShadowRoot();
-
-var shadowElem = document.createElement("shadow");
-youngerShadowRoot.appendChild(shadowElem);
-
-var span = document.createElement("span");
-olderShadowRoot.appendChild(span);
-
-is(span.getDestinationInsertionPoints().length, 1, "Child of ShadowRoot should be distributed to shadow insertion point.");
-is(span.getDestinationInsertionPoints()[0], shadowElem, "Shadow element should be in destination insertion point list.");
-
-// Test destination insertion points of node removed from tree.
-olderShadowRoot.removeChild(span);
-is(span.getDestinationInsertionPoints().length, 0, "Node removed from tree should no longer be distributed.");
-
-// Test destination insertion points of fallback content being reprojected into a shadow element.
-var content = document.createElement("content");
-var fallback = document.createElement("span");
-
-content.appendChild(fallback);
-olderShadowRoot.appendChild(content);
-
-is(fallback.getDestinationInsertionPoints().length, 2, "The fallback content should have 2 destination insertion points, the parent content and the shadow element to which it is reprojected.");
-is(fallback.getDestinationInsertionPoints()[0], content, "First destination of the fallback content should be the parent content element.");
-is(fallback.getDestinationInsertionPoints()[1], shadowElem, "Second destination of the fallback content should be the shadow element to which the element is reprojected.");
-
-// Test destination insertion points of fallback content being removed from tree.
-content.removeChild(fallback);
-is(fallback.getDestinationInsertionPoints().length, 0, "The content should no longer be distributed to any nodes because it is no longer fallback content.");
-
-// Test destination insertion points of distributed content after removing shadow insertion point.
-var div = document.createElement("div");
-olderShadowRoot.appendChild(div);
-is(div.getDestinationInsertionPoints().length, 1, "Children in older shadow root should be distributed to shadow insertion point.");
-is(div.getDestinationInsertionPoints()[0], shadowElem, "Destination insertion point should include shadow element.");
-
-youngerShadowRoot.removeChild(shadowElem);
-is(div.getDestinationInsertionPoints().length, 0, "Destination insertion points should be empty after removing shadow element.");
-
-</script>
-</body>
-</html>

deleted file mode 100644
--- a/dom/tests/mochitest/webcomponents/test_event_dispatch.html
+++ /dev/null
@@ -1,458 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<!--
-https://bugzilla.mozilla.org/show_bug.cgi?id=887541
--->
-<head>
-  <title>Test for event model in web components</title>
-  <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
-  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
-</head>
-<body>
-<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=887541">Bug 887541</a>
-<script>
-
-var els = SpecialPowers.Cc["@mozilla.org/eventlistenerservice;1"]
-            .getService(SpecialPowers.Ci.nsIEventListenerService);
-
-function eventListener(e) {
-  eventChain.push(this);
-}
-
-function isEventChain(actual, expected, msg) {
-  is(actual.length, expected.length, msg);
-  for (var i = 0; i < expected.length; i++) {
-    is(actual[i], expected[i], msg + " at " + i);
-  }
-
-  // Check to make sure the event chain matches what we get back from nsIEventListenerService.getEventTargetChainFor
-  if (0 < actual.length) {
-    var chain = els.getEventTargetChainFor(actual[0], true); // Events should be dispatched on actual[0].
-    for (var i = 0; i < expected.length; i++) {
-      ok(SpecialPowers.compare(chain[i], expected[i]), msg + " at " + i + " for nsIEventListenerService");
-    }
-  }
-}
-
-/*
- * Test 1: Test of event dispatch through a basic ShadowRoot with content a insertion point.
- *
- * <div elemOne> ------ <shadow-root shadowOne>
- *        |                        |
- * <div elemTwo>            <span elemThree>
- *                                 |
- *                         <content elemFour>
- */
-
-var elemOne = document.createElement("div");
-elemOne.addEventListener("custom", eventListener);
-
-var elemTwo = document.createElement("div");
-elemTwo.addEventListener("custom", eventListener);
-
-var elemThree = document.createElement("span");
-elemThree.addEventListener("custom", eventListener);
-
-var elemFour = document.createElement("content");
-elemFour.addEventListener("custom", eventListener);
-
-var shadowOne = elemOne.createShadowRoot();
-shadowOne.addEventListener("custom", eventListener);
-
-elemThree.appendChild(elemFour);
-shadowOne.appendChild(elemThree);
-elemOne.appendChild(elemTwo);
-
-var eventChain = [];
-var customEvent = new CustomEvent("custom", { "bubbles" : true, "composed" : true });
-elemTwo.dispatchEvent(customEvent);
-isEventChain(eventChain, [elemTwo, elemFour, elemThree, shadowOne, elemOne], "Event path for test 1 for event dispatched on elemTwo.");
-
-/*
- * Test 2: Test of event dispatch through a nested ShadowRoots with content insertion points.
- *
- * <div elemFive> --- <shadow-root shadowTwo>
- *       |                       |
- * <div elemOne>          <div elemFour> ----- <shadow-root shadowOne>
- *                               |                        |
- *                       <content elemTwo>           <p elemSix>
- *                                                        |
- *                                               <content elemThree>
- */
-
-elemOne = document.createElement("div");
-elemOne.addEventListener("custom", eventListener);
-
-elemTwo = document.createElement("content");
-elemTwo.addEventListener("custom", eventListener);
-
-elemThree = document.createElement("content");
-elemThree.addEventListener("custom", eventListener);
-
-var elemFour = document.createElement("div");
-elemFour.addEventListener("custom", eventListener);
-
-var elemFive = document.createElement("div");
-elemFive.addEventListener("custom", eventListener);
-
-var elemSix = document.createElement("p");
-elemSix.addEventListener("custom", eventListener);
-
-var shadowOne = elemFour.createShadowRoot();
-shadowOne.addEventListener("custom", eventListener);
-
-var shadowTwo = elemFive.createShadowRoot();
-shadowTwo.addEventListener("custom", eventListener);
-
-elemFive.appendChild(elemOne);
-shadowTwo.appendChild(elemFour);
-elemFour.appendChild(elemTwo);
-shadowOne.appendChild(elemSix);
-elemSix.appendChild(elemThree);
-
-eventChain = [];
-customEvent = new CustomEvent("custom", { "bubbles" : true, "composed" : true });
-elemOne.dispatchEvent(customEvent);
-is(elemOne.getDestinationInsertionPoints().length, 2, "yes");
-isEventChain(eventChain, [elemOne, elemThree, elemSix, shadowOne, elemTwo, elemFour, shadowTwo, elemFive], "Event path for test 2 for event dispatched on elemOne.");
-
-/*
- * Test 3: Test of event dispatch through nested ShadowRoot with content insertion points.
- *
- * <div elemOne> ------- <shadow-root shadowOne>
- *        |                        |
- * <span elemTwo>          <span elemThree> ------------ <shadow-root shadowTwo>
- *                                 |                               |
- *                          <span elemFour>                <content elemSix>
- *                                 |
- *                         <content elemFive>
- */
-
-elemOne = document.createElement("div");
-elemOne.addEventListener("custom", eventListener);
-
-elemTwo = document.createElement("span");
-elemTwo.addEventListener("custom", eventListener);
-
-elemThree = document.createElement("span");
-elemThree.addEventListener("custom", eventListener);
-
-elemFour = document.createElement("span");
-elemFour.addEventListener("custom", eventListener);
-
-elemFive = document.createElement("content");
-elemFive.addEventListener("custom", eventListener);
-
-elemSix = document.createElement("content");
-elemSix.addEventListener("custom", eventListener);
-
-shadowOne = elemOne.createShadowRoot();
-shadowOne.addEventListener("custom", eventListener);
-
-shadowTwo = elemThree.createShadowRoot();
-shadowTwo.addEventListener("custom", eventListener);
-
-elemOne.appendChild(elemTwo);
-shadowOne.appendChild(elemThree);
-elemThree.appendChild(elemFour);
-elemFour.appendChild(elemFive);
-shadowTwo.appendChild(elemSix);
-
-eventChain = [];
-customEvent = new CustomEvent("custom", { "bubbles" : true, "composed" : true });
-elemTwo.dispatchEvent(customEvent);
-isEventChain(eventChain, [elemTwo, elemFive, elemFour, elemSix, shadowTwo, elemThree, shadowOne, elemOne], "Event path for test 3 for event dispatched on elemTwo.");
-
-/*
- * Test 4: Test of event dispatch through host with multiple ShadowRoots with shadow insertion point.
- *
- * <div elemSeven> --- <shadow-root shadowTwo> (younger ShadowRoot)
- *       |         |             |
- * <div elemOne>   |      <div elemSix> -------- <shadow-root shadowOne>
- *                 |             |                         |
- *                 |     <shadow elemFour>         <content elemFive>
- *                 |             |
- *                 |     <content elemTwo>
- *                 |
- *                 --- <shadow-root shadowThree> (older ShadowRoot)
- *                         |                |
- *                         |       <content elemThree>
- *                         |
- *                  <div elemEight>
- */
-
-elemOne = document.createElement("div");
-elemOne.addEventListener("custom", eventListener);
-
-elemTwo = document.createElement("content");
-elemTwo.addEventListener("custom", eventListener);
-
-elemThree = document.createElement("content");
-elemThree.addEventListener("custom", eventListener);
-
-elemFour = document.createElement("shadow");
-elemFour.addEventListener("custom", eventListener);
-
-elemFive = document.createElement("content");
-elemFive.addEventListener("custom", eventListener);
-
-elemSix = document.createElement("div");
-elemSix.addEventListener("custom", eventListener);
-
-var elemSeven = document.createElement("div");
-elemSeven.addEventListener("custom", eventListener);
-
-var elemEight = document.createElement("div");
-elemEight.addEventListener("custom", eventListener);
-
-var shadowThree = elemSeven.createShadowRoot();
-shadowThree.addEventListener("custom", eventListener);
-
-shadowTwo = elemSeven.createShadowRoot();
-shadowTwo.addEventListener("custom", eventListener);
-
-shadowOne = elemSix.createShadowRoot();
-shadowOne.addEventListener("custom", eventListener);
-
-elemSeven.appendChild(elemOne);
-shadowTwo.appendChild(elemSix);
-elemSix.appendChild(elemFour);
-elemFour.appendChild(elemTwo);
-shadowThree.appendChild(elemEight);
-shadowThree.appendChild(elemThree);
-shadowOne.appendChild(elemFive);
-
-eventChain = [];
-customEvent = new CustomEvent("custom", { "bubbles" : true, "composed" : true });
-elemOne.dispatchEvent(customEvent);
-isEventChain(eventChain, [elemOne, elemFive, shadowOne, elemThree, shadowThree, elemTwo, elemFour, elemSix, shadowTwo, elemSeven], "Event path for test 4 for event dispatched on elemOne.");
-
-eventChain = [];
-customEvent = new CustomEvent("custom", { "bubbles" : true, "composed" : true });
-elemEight.dispatchEvent(customEvent);
-isEventChain(eventChain, [elemEight, elemFive, shadowOne, elemSix, shadowTwo, elemSeven], "Event path for test 4 for event dispatched on elemEight.");
-
-/*
- * Test 5: Test of event dispatch through nested shadowroot with insertion points that match specific tags.
- *
- * <div elemOne> --------- <shadow-root shadowOne>
- *    |      |                        |
- *    |  <p elemThree>        <span elemFour> ------------------------ <shadow-root shadowTwo>
- *    |                          |       |                                        |
- * <span elemTwo>                |   <content select="p" elemFive>       <content elemSeven>
- *                               |
- *                       <content select="span" elemSix>
- */
-
-elemOne = document.createElement("div");
-elemOne.addEventListener("custom", eventListener);
-
-elemTwo = document.createElement("span");
-elemTwo.addEventListener("custom", eventListener);
-
-elemThree = document.createElement("p");
-elemThree.addEventListener("custom", eventListener);
-
-elemFour = document.createElement("span");
-elemFour.addEventListener("custom", eventListener);
-
-elemFive = document.createElement("content");
-elemFive.select = "p";
-elemFive.addEventListener("custom", eventListener);
-
-elemSix = document.createElement("content");
-elemSix.select = "span";
-elemSix.addEventListener("custom", eventListener);
-
-elemSeven = document.createElement("content");
-elemSeven.addEventListener("custom", eventListener);
-
-shadowTwo = elemFour.createShadowRoot();
-shadowTwo.addEventListener("custom", eventListener);
-
-shadowOne = elemOne.createShadowRoot();
-shadowOne.addEventListener("custom", eventListener);
-
-elemOne.appendChild(elemTwo);
-elemOne.appendChild(elemThree);
-shadowOne.appendChild(elemFour);
-elemFour.appendChild(elemSix);
-elemFour.appendChild(elemFive);
-shadowTwo.appendChild(elemSeven);
-
-eventChain = [];
-customEvent = new CustomEvent("custom", { "bubbles" : true, "composed" : true });
-elemTwo.dispatchEvent(customEvent);
-isEventChain(eventChain, [elemTwo, elemSeven, shadowTwo, elemSix, elemFour, shadowOne, elemOne], "Event path for test 5 for event dispatched on elemTwo.");
-
-eventChain = [];
-customEvent = new CustomEvent("custom", { "bubbles" : true, "composed" : true });
-elemThree.dispatchEvent(customEvent);
-isEventChain(eventChain, [elemThree, elemSeven, shadowTwo, elemFive, elemFour, shadowOne, elemOne], "Event path for test 5 for event dispatched on elemThree.");
-
-/*
- * Test 6: Test of event dispatch through nested shadowroot with insertion points that match specific tags.
- *
- * <div elemOne> --------- <shadow-root shadowOne>;
- *    |      |                        |
- *    |  <p elemThree>         <span elemFour> ------ <shadow-root shadowTwo>
- *    |                               |                   |            |
- * <span elemTwo>            <content elemFive>           |  <content select="p" elemSeven>
- *                                                        |
- *                                                 <content select="span" elemSix>
- */
-
-elemOne = document.createElement("div");
-elemOne.addEventListener("custom", eventListener);
-
-elemTwo = document.createElement("span");
-elemTwo.addEventListener("custom", eventListener);
-
-elemThree = document.createElement("p");
-elemThree.addEventListener("custom", eventListener);
-
-elemFour = document.createElement("span");
-elemFour.addEventListener("custom", eventListener);
-
-elemFive = document.createElement("content");
-elemFive.addEventListener("custom", eventListener);
-
-elemSix = document.createElement("content");
-elemSix.select = "span";
-elemSix.addEventListener("custom", eventListener);
-
-elemSeven = document.createElement("content");
-elemSeven.select = "p";
-elemSeven.addEventListener("custom", eventListener);
-
-shadowTwo = elemFour.createShadowRoot();
-shadowTwo.addEventListener("custom", eventListener);
-
-shadowOne = elemOne.createShadowRoot();
-shadowOne.addEventListener("custom", eventListener);
-
-elemOne.appendChild(elemTwo);
-elemOne.appendChild(elemThree);
-shadowOne.appendChild(elemFour);
-elemFour.appendChild(elemFive);
-shadowTwo.appendChild(elemSix);
-shadowTwo.appendChild(elemSeven);
-
-eventChain = [];
-customEvent = new CustomEvent("custom", { "bubbles" : true, "composed" : true });
-elemTwo.dispatchEvent(customEvent);
-isEventChain(eventChain, [elemTwo, elemSix, shadowTwo, elemFive, elemFour, shadowOne, elemOne], "Event path for test 6 for event dispatched on elemTwo.");
-
-eventChain = [];
-customEvent = new CustomEvent("custom", { "bubbles" : true, "composed" : true });
-elemThree.dispatchEvent(customEvent);
-isEventChain(eventChain, [elemThree, elemSeven, shadowTwo, elemFive, elemFour, shadowOne, elemOne], "Event path for test 6 for event dispatched on elemThree.");
-
-/*
- * Test 7: Test of event dispatch through nested shadowroot with insertion points that match specific tags.
- *
- * <div elemOne> --------- <shadow-root shadowOne>
- *    |      |                        |
- *    |  <p elemThree>         <span elemFour> ------ <shadow-root shadowTwo>
- *    |                               |                         |
- * <span elemTwo>            <content elemFive>           <span elemEight>
- *                                                           |        |
- *                                                           |   <content select="p" elemSeven>
- *                                                           |
- *                                              <content select="span" elemSix>
- */
-
-elemOne = document.createElement("div");
-elemOne.addEventListener("custom", eventListener);
-
-elemTwo = document.createElement("span");
-elemTwo.addEventListener("custom", eventListener);
-
-elemThree = document.createElement("p");
-elemThree.addEventListener("custom", eventListener);
-
-elemFour = document.createElement("span");
-elemFour.addEventListener("custom", eventListener);
-
-elemFive = document.createElement("content");
-elemFive.addEventListener("custom", eventListener);
-
-elemSix = document.createElement("content");
-elemSix.select = "span";
-elemSix.addEventListener("custom", eventListener);
-
-elemSeven = document.createElement("content");
-elemSeven.select = "p";
-elemSeven.addEventListener("custom", eventListener);
-
-elemEight = document.createElement("span");
-elemEight.addEventListener("custom", eventListener);
-
-shadowTwo = elemFour.createShadowRoot();
-shadowTwo.addEventListener("custom", eventListener);
-
-shadowOne = elemOne.createShadowRoot();
-shadowOne.addEventListener("custom", eventListener);
-
-elemOne.appendChild(elemTwo);
-elemOne.appendChild(elemThree);
-shadowOne.appendChild(elemFour);
-elemFour.appendChild(elemFive);
-shadowTwo.appendChild(elemEight);
-elemEight.appendChild(elemSix);
-elemEight.appendChild(elemSeven);
-
-eventChain = [];
-customEvent = new CustomEvent("custom", { "bubbles" : true, "composed" : true });
-elemTwo.dispatchEvent(customEvent);
-isEventChain(eventChain, [elemTwo, elemSix, elemEight, shadowTwo, elemFive, elemFour, shadowOne, elemOne], "Event path for test 7 for event dispatched on elemTwo.");
-
-eventChain = [];
-customEvent = new CustomEvent("custom", { "bubbles" : true, "composed" : true });
-elemThree.dispatchEvent(customEvent);
-isEventChain(eventChain, [elemThree, elemSeven, elemEight, shadowTwo, elemFive, elemFour, shadowOne, elemOne], "Event path for test 7 for event dispatched on elemThree.");
-
-/*
- * Test 8: Test of event dispatch through host with multiple ShadowRoots with shadow insertion point.
- *
- * <div elemOne> --- <shadow-root shadowOne> (younger ShadowRoot)
- *               |             |
- *               |      <div elemFour>
- *               |             |
- *               |     <shadow elemTwo>
- *               |
- *               --- <shadow-root shadowTwo> (older ShadowRoot)
- *                             |
- *                      <div elemThree>
- */
-
-elemOne = document.createElement("div");
-elemOne.addEventListener("custom", eventListener);
-
-elemTwo = document.createElement("shadow");
-elemTwo.addEventListener("custom", eventListener);
-
-elemThree = document.createElement("div");
-elemThree.addEventListener("custom", eventListener);
-
-elemFour = document.createElement("div");
-elemFour.addEventListener("custom", eventListener);
-
-shadowTwo = elemOne.createShadowRoot();
-shadowTwo.addEventListener("custom", eventListener);
-
-shadowOne = elemOne.createShadowRoot();
-shadowOne.addEventListener("custom", eventListener);
-
-shadowOne.appendChild(elemFour);
-elemFour.appendChild(elemTwo);
-shadowTwo.appendChild(elemThree);
-
-eventChain = [];
-customEvent = new CustomEvent("custom", { "bubbles" : true, "composed" : true });
-elemThree.dispatchEvent(customEvent);
-isEventChain(eventChain, [elemThree, shadowTwo, elemTwo, elemFour, shadowOne, elemOne], "Event path for test 8 for event dispatched on elemThree.");
-
-</script>
-</body>
-</html>

deleted file mode 100644
--- a/dom/tests/mochitest/webcomponents/test_shadowroot_host.html
+++ /dev/null
@@ -1,41 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<!--
-https://bugzilla.mozilla.org/show_bug.cgi?id=1083587
--->
-<head>
-  <meta charset="utf-8">
-  <title>Test for Bug 1083587</title>
-  <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
-  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
-</head>
-<body>
-<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1083587">Mozilla Bug 1083587</a>
-<p id="display"></p>
-<div id="content" style="display: none">
-<div id="host"></div>
-</div>
-<pre id="test">
-</pre>
-<script type="application/javascript">
-
-/** Test for Bug 1083587 **/
-var hostInDoc = document.getElementById("host");
-var shadowOne = hostInDoc.createShadowRoot();
-is(shadowOne.host, hostInDoc);
-
-var shadowTwo = hostInDoc.createShadowRoot();
-is(shadowOne.host, hostInDoc);
-is(shadowTwo.host, hostInDoc);
-
-var hostNotInDoc = document.createElement("div");
-var shadowThree = hostNotInDoc.createShadowRoot();
-is(shadowThree.host, hostNotInDoc);
-
-var shadowFour = hostNotInDoc.createShadowRoot();
-is(shadowThree.host, hostNotInDoc);
-is(shadowFour.host, hostNotInDoc);
-
-</script>
-</body>
-</html>

deleted file mode 100644
--- a/dom/tests/mochitest/webcomponents/test_shadowroot_style_multiple_shadow.html
+++ /dev/null
@@ -1,57 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<!--
-https://bugzilla.mozilla.org/show_bug.cgi?id=806506
--->
-<head>
-  <title>Test for ShadowRoot styles with multiple ShadowRoot on host.</title>
-  <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
-  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
-</head>
-<body>
-<div class="tall" id="bodydiv"></div>
-<div id="container"></div>
-<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=806506">Bug 806506</a>
-<script>
-// Create ShadowRoot.
-var container = document.getElementById("container");
-var elem = document.createElement("div");
-container.appendChild(elem); // Put ShadowRoot host in document.
-var firstRoot = elem.createShadowRoot();
-var secondRoot = elem.createShadowRoot();
-var thirdRoot = elem.createShadowRoot();
-
-// A style element that will be appended into the ShadowRoot.
-var firstStyle = document.createElement("style");
-firstRoot.appendChild(firstStyle);
-is(firstRoot.styleSheets.length, 1, "firstStyle should be the only style in firstRoot.");
-is(firstRoot.styleSheets[0].ownerNode, firstStyle, "firstStyle should in the ShadowRoot styleSheets.");
-
-var secondStyle = document.createElement("style");
-secondRoot.appendChild(secondStyle);
-is(secondRoot.styleSheets.length, 1, "secondStyle should be the only style in secondRoot.");
-is(secondRoot.styleSheets[0].ownerNode, secondStyle, "secondStyle should in the ShadowRoot styleSheets.");
-
-var thirdStyle = document.createElement("style");
-thirdRoot.appendChild(thirdStyle);
-is(thirdRoot.styleSheets.length, 1, "thirdStyle should be the only style in thirdRoot.");
-is(thirdRoot.styleSheets[0].ownerNode, thirdStyle, "thirdStyle should in the ShadowRoot styleSheets.");
-
-// Check the stylesheet counts again to make sure that none of the style sheets leaked into the older ShadowRoots.
-is(firstRoot.styleSheets.length, 1, "Adding a stylesheet to a younger ShadowRoot should not affect stylesheets in the older ShadowRoot.");
-is(secondRoot.styleSheets.length, 1, "Adding a stylesheet to a younger ShadowRoot should not affect stylesheets in the older ShadowRoot.");
-
-// Remove styles and make sure they are removed from the correct ShadowRoot.
-firstRoot.removeChild(firstStyle);
-is(firstRoot.styleSheets.length, 0, "firstRoot should no longer have any styles.");
-
-thirdRoot.removeChild(thirdStyle);
-is(thirdRoot.styleSheets.length, 0, "thirdRoot should no longer have any styles.");
-
-secondRoot.removeChild(secondStyle);
-is(secondRoot.styleSheets.length, 0, "secondRoot should no longer have any styles.");
-
-</script>
-</body>
-</html>
-

deleted file mode 100644
--- a/dom/tests/mochitest/webcomponents/test_shadowroot_youngershadowroot.html
+++ /dev/null
@@ -1,41 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<!--
-https://bugzilla.mozilla.org/show_bug.cgi?id=1083587
--->
-<head>
-  <meta charset="utf-8">
-  <title>Test for Bug 1083587</title>
-  <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
-  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
-</head>
-<body>
-<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1083587">Mozilla Bug 1083587</a>
-<p id="display"></p>
-<div id="content" style="display: none">
-<div id="host"></div>
-</div>
-<pre id="test">
-</pre>
-<script type="application/javascript">
-
-/** Test for Bug 1083587 **/
-var hostInDoc = document.getElementById("host");
-var shadowOne = hostInDoc.createShadowRoot();
-is(shadowOne.olderShadowRoot, null);
-
-var shadowTwo = hostInDoc.createShadowRoot();
-is(shadowOne.olderShadowRoot, null);
-is(shadowTwo.olderShadowRoot, shadowOne);
-
-var hostNotInDoc = document.createElement("div");
-var shadowThree = hostNotInDoc.createShadowRoot();
-is(shadowThree.olderShadowRoot, null);
-
-var shadowFour = hostNotInDoc.createShadowRoot();
-is(shadowThree.olderShadowRoot, null);
-is(shadowFour.olderShadowRoot, shadowThree);
-
-</script>
-</body>
-</html>

deleted file mode 100644
--- a/dom/webidl/HTMLShadowElement.webidl
+++ /dev/null
@@ -1,19 +0,0 @@
-/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this file,
- * You can obtain one at http://mozilla.org/MPL/2.0/.
- *
- * The origin of this IDL file is
- * https://dvcs.w3.org/hg/webcomponents/raw-file/tip/spec/shadow/index.html
- *
- * © Copyright 2004-2011 Apple Computer, Inc., Mozilla Foundation, and
- * Opera Software ASA. You are granted a license to use, reproduce
- * and create derivative works of this document.
- */
-
-[Func="nsDocument::IsWebComponentsEnabled"]
-interface HTMLShadowElement : HTMLElement
-{
-  readonly attribute ShadowRoot? olderShadowRoot;
-};
-

--- a/dom/webidl/ShadowRoot.webidl
+++ b/dom/webidl/ShadowRoot.webidl
@@ -15,13 +15,12 @@ interface ShadowRoot : DocumentFragment
 {
   Element? getElementById(DOMString elementId);
   HTMLCollection getElementsByTagName(DOMString localName);
   HTMLCollection getElementsByTagNameNS(DOMString? namespace, DOMString localName);
   HTMLCollection getElementsByClassName(DOMString classNames);
   [CEReactions, SetterThrows, TreatNullAs=EmptyString]
   attribute DOMString innerHTML;
   readonly attribute Element host;
-  readonly attribute ShadowRoot? olderShadowRoot;
   attribute boolean applyAuthorStyles;
   readonly attribute StyleSheetList styleSheets;
 };
 

--- a/dom/webidl/moz.build
+++ b/dom/webidl/moz.build
@@ -611,17 +611,16 @@ WEBIDL_FILES = [
     'HTMLParagraphElement.webidl',
     'HTMLParamElement.webidl',
     'HTMLPictureElement.webidl',
     'HTMLPreElement.webidl',
     'HTMLProgressElement.webidl',
     'HTMLQuoteElement.webidl',
     'HTMLScriptElement.webidl',
     'HTMLSelectElement.webidl',
-    'HTMLShadowElement.webidl',
     'HTMLSourceElement.webidl',
     'HTMLSpanElement.webidl',
     'HTMLStyleElement.webidl',
     'HTMLTableCaptionElement.webidl',
     'HTMLTableCellElement.webidl',
     'HTMLTableColElement.webidl',
     'HTMLTableElement.webidl',
     'HTMLTableRowElement.webidl',

--- a/editor/libeditor/HTMLEditUtils.cpp
+++ b/editor/libeditor/HTMLEditUtils.cpp
@@ -715,17 +715,16 @@ static const ElementInfo kElements[eHTML
   ELEM(rtc, true, true, GROUP_PHRASE, GROUP_INLINE_ELEMENT),
   ELEM(ruby, true, true, GROUP_PHRASE, GROUP_INLINE_ELEMENT),
   ELEM(s, true, true, GROUP_FONTSTYLE, GROUP_INLINE_ELEMENT),
   ELEM(samp, true, true, GROUP_PHRASE, GROUP_INLINE_ELEMENT),
   ELEM(script, true, false, GROUP_HEAD_CONTENT | GROUP_SPECIAL,
        GROUP_LEAF),
   ELEM(section, true, true, GROUP_BLOCK, GROUP_FLOW_ELEMENT),
   ELEM(select, true, false, GROUP_FORMCONTROL, GROUP_SELECT_CONTENT),
-  ELEM(shadow, true, false, GROUP_NONE, GROUP_INLINE_ELEMENT),
   ELEM(small, true, true, GROUP_FONTSTYLE, GROUP_INLINE_ELEMENT),
   ELEM(source, false, false, GROUP_PICTURE_CONTENT, GROUP_NONE),
   ELEM(span, true, true, GROUP_SPECIAL, GROUP_INLINE_ELEMENT),
   ELEM(strike, true, true, GROUP_FONTSTYLE, GROUP_INLINE_ELEMENT),
   ELEM(strong, true, true, GROUP_PHRASE, GROUP_INLINE_ELEMENT),
   ELEM(style, true, false, GROUP_HEAD_CONTENT, GROUP_LEAF),
   ELEM(sub, true, true, GROUP_SPECIAL, GROUP_INLINE_ELEMENT),
   ELEM(summary, true, true, GROUP_BLOCK, GROUP_FLOW_ELEMENT),

--- a/layout/reftests/css-display/display-contents-shadow-dom-1-ref.html
+++ b/layout/reftests/css-display/display-contents-shadow-dom-1-ref.html
@@ -40,13 +40,11 @@ span { color:blue; }
     <div><b>One</b><i>Two</i></div>
     <div><b>One</b><i>Two</i></div>
     <div><b>One</b><i>Two</i></div>
     <div><b>One</b><i>Two</i></div>
     <b style="color:blue">One</b><i style="color:blue">Two</i>Three
     <span style="color:green">R</span>
     <div></div>
     <b style="color:green">V</b>
-    <b style="color:green">W</b>
-    <b style="color:green">X</b>
     <!-- <b style="color:green">Y</b> -->
   </body>
 </html>

--- a/layout/reftests/css-display/display-contents-shadow-dom-1.html
+++ b/layout/reftests/css-display/display-contents-shadow-dom-1.html
@@ -46,18 +46,16 @@ div.after::after {content: " Y";}
     <div id="hostO"><i>Two</i><b class="c">One</b></div>
     <div id="hostP"><i class="c">Two</i><b class="c">One</b></div>
     <div id="hostQ" class="c" style="color:blue"><i class="c">Two</i><b class="c">One</b></div>Three
     <span id="hostR"><style scoped>:scope{color:green}</style></span>
     <div id="hostS" class="c"><span class="c">S</span></div>
     <div id="hostT" class="c">T</div>
     <div id="hostU"><span class="c">U</span></div>
     <div id="hostV" class="c" style="color:red"><b class="c" style="color:inherit">V</b></div>
-    <div id="hostW" class="c" style="color:red"><b class="c" style="color:inherit">W</b></div>
-    <span id="hostX" style="color:red"><b class="c" style="color:inherit">X</b></span>
     <!-- TODO(bug 1021572?) <div id="hostY" class="c" style="color:red"><b>Y</b></div> -->
 
    <script>
       function shadow(id) {
         return document.getElementById(id).createShadowRoot();
       }
       function span(s) {
         var e = document.createElement("span");
@@ -101,18 +99,16 @@ div.after::after {content: " Y";}
         shadow("hostK").innerHTML = '<content select=".b"></content>';
         shadow("hostL").innerHTML = '<content select=".b"></content>';
         shadow("hostM").innerHTML = '<content select="b"></content><content select="i"></content>';
         shadow("hostN").innerHTML = '<content select="b"></content><content select="i"></content>';
         shadow("hostO").innerHTML = '<content select="b"></content><content select="i"></content>';
         shadow("hostP").innerHTML = '<content select="b"></content><content select="i"></content>';
         shadow("hostQ").innerHTML = '<content select="b"></content><content select="i"></content>';
         shadow("hostR").innerHTML = '<content select="span"></content>';
-        shadow("hostW").innerHTML = '<z style="color:red"><content select="b"></content></z>';
-        shadow("hostX").innerHTML = '<z style="color:red"><content select="b"></content></z>';
         // TODO(bug 1021572?) shadow("hostY").innerHTML = '<content select="b"><style scoped>:scope{color:green}</style></content>';
       }
 
       function tweak() {
         document.body.offsetHeight;
 
         host1.appendChild(span("1"));
         host2.appendChild(text("2"));
@@ -219,18 +215,16 @@ div.after::after {content: " Y";}
         hostR.appendChild(span("R"));
 
         document.body.offsetHeight;
         setTimeout(function() {
             shadow("hostS");
             shadow("hostT");
             shadow("hostU");
             shadow("hostV").innerHTML = '<z style="color:green"><content select="b"></content></z>';
-            shadow("hostW").innerHTML = '<z style="color:green"><content select="b"></content></z>';
-            shadow("hostX").innerHTML = '<z style="color:green"><content select="b"></content></z>';
 
             document.body.offsetHeight;
             document.documentElement.removeAttribute("class");
           },0);
       }
 
       if (document.body.createShadowRoot) {
         run();

deleted file mode 100644
--- a/layout/reftests/webcomponents/adjacent-insertion-points-1-ref.html
+++ /dev/null
@@ -1,6 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<body>
-<div><span>Hello</span><span>World</span></div>
-</body>
-</html>

deleted file mode 100644
--- a/layout/reftests/webcomponents/adjacent-insertion-points-1.html
+++ /dev/null
@@ -1,17 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<head>
-  <script>
-    function tweak() {
-      var oldShadowRoot = document.getElementById('outer').createShadowRoot();
-      oldShadowRoot.innerHTML = 'World';
-
-      var youngShadowRoot = document.getElementById('outer').createShadowRoot();
-      youngShadowRoot.innerHTML = 'Hello<content></content><shadow></shadow>';
-    }
-  </script>
-</head>
-<body onload="tweak()">
-<div id="outer"></div>
-</body>
-</html>

deleted file mode 100644
--- a/layout/reftests/webcomponents/adjacent-insertion-points-2-ref.html
+++ /dev/null
@@ -1,6 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<body>
-<div><span>Hello</span><span>World</span></div>
-</body>
-</html>

deleted file mode 100644
--- a/layout/reftests/webcomponents/adjacent-insertion-points-2.html
+++ /dev/null
@@ -1,17 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<head>
-  <script>
-    function tweak() {
-      var oldShadowRoot = document.getElementById('outer').createShadowRoot();
-      oldShadowRoot.innerHTML = 'Hello';
-
-      var youngShadowRoot = document.getElementById('outer').createShadowRoot();
-      youngShadowRoot.innerHTML = '<shadow></shadow><content></content>World';
-    }
-  </script>
-</head>
-<body onload="tweak()">
-<div id="outer"></div>
-</body>
-</html>

deleted file mode 100644
--- a/layout/reftests/webcomponents/basic-shadow-element-1-ref.html
+++ /dev/null
@@ -1,10 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<head>
-</head>
-<body>
-<div>
-  <div style="width:100px; height:100px; background-color:green"></div><div style="width:100px; height:100px; background-color:orange">Hello World</div>
-</div>
-</body>
-</html>

deleted file mode 100644
--- a/layout/reftests/webcomponents/basic-shadow-element-1.html
+++ /dev/null
@@ -1,19 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<head>
-  <script>
-    function tweak() {
-      var olderShadow = document.getElementById('outer').createShadowRoot();
-      olderShadow.innerHTML = '<div style="width:100px; height:100px; background-color: orange"><content></content></div>';
-
-      var youngerShadow = document.getElementById('outer').createShadowRoot();
-      youngerShadow.innerHTML = '<div style="width:100px; height:100px; background-color: green"></div><shadow>Hello World</shadow>';
-    }
-  </script>
-</head>
-<body onload="tweak()">
-<div id="outer">
-  <div style="width:300px; height:100px; background-color:red;"></div>
-</div>
-</body>
-</html>

deleted file mode 100644
--- a/layout/reftests/webcomponents/nested-shadow-element-1-ref.html
+++ /dev/null
@@ -1,10 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<head>
-</head>
-<body>
-<div>
-  <div style="background-color: green"><span>Hello</span><span> </span><span>World</span></div>
-</div>
-</body>
-</html>

deleted file mode 100644
--- a/layout/reftests/webcomponents/nested-shadow-element-1.html
+++ /dev/null
@@ -1,29 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<head>
-  <script>
-    function tweak() {
-      var olderShadow = document.getElementById('outer').createShadowRoot();
-      olderShadow.innerHTML = '<content></content><span>World</span>';
-
-      var youngerShadow = document.getElementById('outer').createShadowRoot();
-      youngerShadow.innerHTML = '<div id="shadowparent"><shadow id="youngshadow"><span>Hello</span></shadow></div>';
-
-      var shadowParent = youngerShadow.getElementById("shadowparent");
-      var nestedShadow = shadowParent.createShadowRoot();
-      nestedShadow.innerHTML = '<div style="background-color: green"><content></content></div>';
-
-      // Dynamically append a span to the shadow element in the younger ShadowRoot to make sure
-      // it is projected into the nested shadow.
-      var appendedSpan = document.createElement("span");
-      appendedSpan.textContent = ' ';
-      youngerShadow.getElementById("youngshadow").appendChild(appendedSpan);
-    }
-  </script>
-</head>
-<body onload="tweak()">
-<div id="outer">
-  <div style="width:300px; height:100px; background-color:red;"></div>
-</div>
-</body>
-</html>

--- a/layout/reftests/webcomponents/reftest.list
+++ b/layout/reftests/webcomponents/reftest.list
@@ -1,19 +1,15 @@
 pref(dom.webcomponents.enabled,true) fails-if(stylo||styloVsGecko) == cross-tree-selection-1.html cross-tree-selection-1-ref.html
 pref(dom.webcomponents.enabled,true) fails-if(stylo||styloVsGecko) == basic-shadow-1.html basic-shadow-1-ref.html
 pref(dom.webcomponents.enabled,true) fails-if(stylo||styloVsGecko) == basic-shadow-2.html basic-shadow-2-ref.html
 pref(dom.webcomponents.enabled,true) fails-if(stylo||styloVsGecko) == basic-shadow-3.html basic-shadow-3-ref.html
 pref(dom.webcomponents.enabled,true) fails-if(stylo||styloVsGecko) == basic-shadow-4.html basic-shadow-4-ref.html
 pref(dom.webcomponents.enabled,true) fails-if(stylo||styloVsGecko) == basic-insertion-point-1.html basic-insertion-point-1-ref.html
 pref(dom.webcomponents.enabled,true) fails-if(stylo||styloVsGecko) == basic-insertion-point-2.html basic-insertion-point-2-ref.html
-pref(dom.webcomponents.enabled,true) fails-if(stylo||styloVsGecko) == adjacent-insertion-points-1.html adjacent-insertion-points-1-ref.html
-pref(dom.webcomponents.enabled,true) fails-if(stylo||styloVsGecko) == adjacent-insertion-points-2.html adjacent-insertion-points-2-ref.html
 pref(dom.webcomponents.enabled,true) fails-if(stylo||styloVsGecko) == fallback-content-1.html fallback-content-1-ref.html
 pref(dom.webcomponents.enabled,true) fails-if(stylo||styloVsGecko) == remove-insertion-point-1.html remove-insertion-point-1-ref.html
 pref(dom.webcomponents.enabled,true) fails-if(stylo||styloVsGecko) == nested-insertion-point-1.html nested-insertion-point-1-ref.html
-pref(dom.webcomponents.enabled,true) fails-if(stylo||styloVsGecko) == basic-shadow-element-1.html basic-shadow-element-1-ref.html
-pref(dom.webcomponents.enabled,true) fails-if(stylo||styloVsGecko) == nested-shadow-element-1.html nested-shadow-element-1-ref.html
 pref(dom.webcomponents.enabled,true) fails-if(stylo||styloVsGecko) == update-dist-node-descendants-1.html update-dist-node-descendants-1-ref.html
 pref(dom.webcomponents.enabled,true) fails-if(stylo||styloVsGecko) fuzzy-if(Android,2,7) == input-transition-1.html input-transition-1-ref.html
 pref(dom.webcomponents.enabled,true) fails-if(stylo||styloVsGecko) == dynamic-insertion-point-distribution-1.html dynamic-insertion-point-distribution-1-ref.html
 pref(dom.webcomponents.enabled,true) fails-if(stylo||styloVsGecko) == dynamic-insertion-point-distribution-2.html dynamic-insertion-point-distribution-2-ref.html
 pref(dom.webcomponents.enabled,true) fails-if(stylo||styloVsGecko) == remove-append-shadow-host-1.html remove-append-shadow-host-1-ref.html

--- a/parser/html/javasrc/ElementName.java
+++ b/parser/html/javasrc/ElementName.java
@@ -354,17 +354,17 @@ public final class ElementName
 //        return "NS_NewSVGUnknownElement";
 //    }
 //
 //    /**
 //     * @see java.lang.Object#toString()
 //     */
 //    @Override public String toString() {
 //        return "(\"" + name + "\", \"" + camelCaseName + "\", \n// CPP"
-//                + "ONLY: " + htmlCreator(name) + ",\n//CPP" + "ONLY: "
+//                + "ONLY: " + htmlCreator(name) + ",\n// CPP" + "ONLY: "
 //                + svgCreator(camelCaseName) + ", \n" + decomposedFlags() + ")";
 //    }
 //
 //    private String decomposedFlags() {
 //        StringBuilder buf = new StringBuilder("TreeBuilder.");
 //        buf.append(treeBuilderGroupToName());
 //        if ((flags & SPECIAL) != 0) {
 //            buf.append(" | SPECIAL");
@@ -650,1202 +650,1249 @@ public final class ElementName
 //            System.err.println("Missing HTML element: " + entry.getKey());
 //        }
 //        for (Entry<String, String> entry : svgMap.entrySet()) {
 //            System.err.println("Missing SVG element: " + entry.getKey());
 //        }
 //    }
 
     // START GENERATED CODE
-    public static final ElementName BIG = new ElementName("big", "big",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.B_OR_BIG_OR_CODE_OR_EM_OR_I_OR_S_OR_SMALL_OR_STRIKE_OR_STRONG_OR_TT_OR_U);
-
-    public static final ElementName BDO = new ElementName("bdo", "bdo",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName COL = new ElementName("col", "col",
-            // CPPONLY: NS_NewHTMLTableColElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.COL | SPECIAL);
-
-    public static final ElementName DEL = new ElementName("del", "del",
-            // CPPONLY: NS_NewHTMLModElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName DFN = new ElementName("dfn", "dfn",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName DIR = new ElementName("dir", "dir",
-            // CPPONLY: NS_NewHTMLSharedElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.ADDRESS_OR_ARTICLE_OR_ASIDE_OR_DETAILS_OR_DIALOG_OR_DIR_OR_FIGCAPTION_OR_FIGURE_OR_FOOTER_OR_HEADER_OR_HGROUP_OR_MAIN_OR_NAV_OR_SECTION_OR_SUMMARY
-                    | SPECIAL);
-
-    public static final ElementName DIV = new ElementName("div", "div",
-            // CPPONLY: NS_NewHTMLDivElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.DIV_OR_BLOCKQUOTE_OR_CENTER_OR_MENU | SPECIAL);
-
-    public static final ElementName IMG = new ElementName("img", "img",
-            // CPPONLY: NS_NewHTMLImageElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.IMG | SPECIAL);
-
-    public static final ElementName INS = new ElementName("ins", "ins",
-            // CPPONLY: NS_NewHTMLModElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName KBD = new ElementName("kbd", "kbd",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName MAP = new ElementName("map", "map",
-            // CPPONLY: NS_NewHTMLMapElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName NAV = new ElementName("nav", "nav",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.ADDRESS_OR_ARTICLE_OR_ASIDE_OR_DETAILS_OR_DIALOG_OR_DIR_OR_FIGCAPTION_OR_FIGURE_OR_FOOTER_OR_HEADER_OR_HGROUP_OR_MAIN_OR_NAV_OR_SECTION_OR_SUMMARY
-                    | SPECIAL);
-
-    public static final ElementName PRE = new ElementName("pre", "pre",
-            // CPPONLY: NS_NewHTMLPreElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.PRE_OR_LISTING | SPECIAL);
-
-    public static final ElementName A = new ElementName("a", "a",
-            // CPPONLY: NS_NewHTMLAnchorElement,
-            // CPPONLY: NS_NewSVGAElement,
-            TreeBuilder.A);
-
-    public static final ElementName B = new ElementName("b", "b",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.B_OR_BIG_OR_CODE_OR_EM_OR_I_OR_S_OR_SMALL_OR_STRIKE_OR_STRONG_OR_TT_OR_U);
-
-    public static final ElementName RTC = new ElementName("rtc", "rtc",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.RB_OR_RTC | OPTIONAL_END_TAG);
-
-    public static final ElementName SUB = new ElementName("sub", "sub",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.RUBY_OR_SPAN_OR_SUB_OR_SUP_OR_VAR);
-
-    public static final ElementName SVG = new ElementName("svg", "svg",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGSVGElement,
-            TreeBuilder.SVG);
-
-    public static final ElementName SUP = new ElementName("sup", "sup",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.RUBY_OR_SPAN_OR_SUB_OR_SUP_OR_VAR);
-
-    public static final ElementName SET = new ElementName("set", "set",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGSetElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName USE = new ElementName("use", "use",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGUseElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName VAR = new ElementName("var", "var",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.RUBY_OR_SPAN_OR_SUB_OR_SUP_OR_VAR);
-
-    public static final ElementName G = new ElementName("g", "g",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGGElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName WBR = new ElementName("wbr", "wbr",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.AREA_OR_WBR | SPECIAL);
-
-    public static final ElementName XMP = new ElementName("xmp", "xmp",
-            // CPPONLY: NS_NewHTMLPreElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.XMP | SPECIAL);
-
-    public static final ElementName I = new ElementName("i", "i",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.B_OR_BIG_OR_CODE_OR_EM_OR_I_OR_S_OR_SMALL_OR_STRIKE_OR_STRONG_OR_TT_OR_U);
-
-    public static final ElementName P = new ElementName("p", "p",
-            // CPPONLY: NS_NewHTMLParagraphElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.P | SPECIAL | OPTIONAL_END_TAG);
-
-    public static final ElementName Q = new ElementName("q", "q",
-            // CPPONLY: NS_NewHTMLSharedElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName S = new ElementName("s", "s",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.B_OR_BIG_OR_CODE_OR_EM_OR_I_OR_S_OR_SMALL_OR_STRIKE_OR_STRONG_OR_TT_OR_U);
-
-    public static final ElementName U = new ElementName("u", "u",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.B_OR_BIG_OR_CODE_OR_EM_OR_I_OR_S_OR_SMALL_OR_STRIKE_OR_STRONG_OR_TT_OR_U);
-
-    public static final ElementName H1 = new ElementName("h1", "h1",
-            // CPPONLY: NS_NewHTMLHeadingElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.H1_OR_H2_OR_H3_OR_H4_OR_H5_OR_H6 | SPECIAL);
-
-    public static final ElementName H2 = new ElementName("h2", "h2",
-            // CPPONLY: NS_NewHTMLHeadingElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.H1_OR_H2_OR_H3_OR_H4_OR_H5_OR_H6 | SPECIAL);
-
-    public static final ElementName H3 = new ElementName("h3", "h3",
-            // CPPONLY: NS_NewHTMLHeadingElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.H1_OR_H2_OR_H3_OR_H4_OR_H5_OR_H6 | SPECIAL);
-
-    public static final ElementName H4 = new ElementName("h4", "h4",
-            // CPPONLY: NS_NewHTMLHeadingElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.H1_OR_H2_OR_H3_OR_H4_OR_H5_OR_H6 | SPECIAL);
-
-    public static final ElementName H5 = new ElementName("h5", "h5",
-            // CPPONLY: NS_NewHTMLHeadingElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.H1_OR_H2_OR_H3_OR_H4_OR_H5_OR_H6 | SPECIAL);
-
-    public static final ElementName H6 = new ElementName("h6", "h6",
-            // CPPONLY: NS_NewHTMLHeadingElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.H1_OR_H2_OR_H3_OR_H4_OR_H5_OR_H6 | SPECIAL);
-
-    public static final ElementName AREA = new ElementName("area", "area",
-            // CPPONLY: NS_NewHTMLAreaElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.AREA_OR_WBR | SPECIAL);
-
-    public static final ElementName DATA = new ElementName("data", "data",
-            // CPPONLY: NS_NewHTMLDataElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName FEFUNCA = new ElementName("fefunca",
-            "feFuncA",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGFEFuncAElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName METADATA = new ElementName("metadata",
-            "metadata",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGMetadataElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName META = new ElementName("meta", "meta",
-            // CPPONLY: NS_NewHTMLMetaElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.META | SPECIAL);
-
-    public static final ElementName TEXTAREA = new ElementName("textarea",
-            "textarea",
-            // CPPONLY: NS_NewHTMLTextAreaElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.TEXTAREA | SPECIAL);
-
-    public static final ElementName FEFUNCB = new ElementName("fefuncb",
-            "feFuncB",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGFEFuncBElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName RB = new ElementName("rb", "rb",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.RB_OR_RTC | OPTIONAL_END_TAG);
-
-    public static final ElementName DESC = new ElementName("desc", "desc",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGDescElement,
-            TreeBuilder.FOREIGNOBJECT_OR_DESC | SCOPING_AS_SVG);
-
-    public static final ElementName DD = new ElementName("dd", "dd",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.DD_OR_DT | SPECIAL | OPTIONAL_END_TAG);
-
-    public static final ElementName BGSOUND = new ElementName("bgsound",
-            "bgsound",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.LINK_OR_BASEFONT_OR_BGSOUND | SPECIAL);
-
-    public static final ElementName EMBED = new ElementName("embed", "embed",
-            // CPPONLY: NS_NewHTMLEmbedElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.EMBED | SPECIAL);
-
-    public static final ElementName FEBLEND = new ElementName("feblend",
-            "feBlend",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGFEBlendElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName FEFLOOD = new ElementName("feflood",
-            "feFlood",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGFEFloodElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName HEAD = new ElementName("head", "head",
-            // CPPONLY: NS_NewHTMLSharedElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.HEAD | SPECIAL | OPTIONAL_END_TAG);
-
-    public static final ElementName LEGEND = new ElementName("legend", "legend",
-            // CPPONLY: NS_NewHTMLLegendElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName NOEMBED = new ElementName("noembed",
-            "noembed",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.NOEMBED | SPECIAL);
-
-    public static final ElementName TD = new ElementName("td", "td",
-            // CPPONLY: NS_NewHTMLTableCellElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.TD_OR_TH | SPECIAL | SCOPING | OPTIONAL_END_TAG);
-
-    public static final ElementName THEAD = new ElementName("thead", "thead",
-            // CPPONLY: NS_NewHTMLTableSectionElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.TBODY_OR_THEAD_OR_TFOOT | SPECIAL | FOSTER_PARENTING
-                    | OPTIONAL_END_TAG);
-
-    public static final ElementName ASIDE = new ElementName("aside", "aside",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.ADDRESS_OR_ARTICLE_OR_ASIDE_OR_DETAILS_OR_DIALOG_OR_DIR_OR_FIGCAPTION_OR_FIGURE_OR_FOOTER_OR_HEADER_OR_HGROUP_OR_MAIN_OR_NAV_OR_SECTION_OR_SUMMARY
-                    | SPECIAL);
-
-    public static final ElementName ARTICLE = new ElementName("article",
-            "article",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.ADDRESS_OR_ARTICLE_OR_ASIDE_OR_DETAILS_OR_DIALOG_OR_DIR_OR_FIGCAPTION_OR_FIGURE_OR_FOOTER_OR_HEADER_OR_HGROUP_OR_MAIN_OR_NAV_OR_SECTION_OR_SUMMARY
-                    | SPECIAL);
-
-    public static final ElementName ANIMATE = new ElementName("animate",
-            "animate",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGAnimateElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName BASE = new ElementName("base", "base",
-            // CPPONLY: NS_NewHTMLSharedElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.BASE | SPECIAL);
-
-    public static final ElementName BLOCKQUOTE = new ElementName("blockquote",
-            "blockquote",
-            // CPPONLY: NS_NewHTMLSharedElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.DIV_OR_BLOCKQUOTE_OR_CENTER_OR_MENU | SPECIAL);
-
-    public static final ElementName CODE = new ElementName("code", "code",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.B_OR_BIG_OR_CODE_OR_EM_OR_I_OR_S_OR_SMALL_OR_STRIKE_OR_STRONG_OR_TT_OR_U);
-
-    public static final ElementName CIRCLE = new ElementName("circle", "circle",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGCircleElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName CITE = new ElementName("cite", "cite",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName ELLIPSE = new ElementName("ellipse",
-            "ellipse",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGEllipseElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName FETURBULENCE = new ElementName(
-            "feturbulence", "feTurbulence",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGFETurbulenceElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName FEMERGENODE = new ElementName("femergenode",
-            "feMergeNode",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGFEMergeNodeElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName FEIMAGE = new ElementName("feimage",
-            "feImage",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGFEImageElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName FEMERGE = new ElementName("femerge",
-            "feMerge",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGFEMergeElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName FETILE = new ElementName("fetile", "feTile",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGFETileElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName FRAME = new ElementName("frame", "frame",
-            // CPPONLY: NS_NewHTMLFrameElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.FRAME | SPECIAL);
-
-    public static final ElementName FIGURE = new ElementName("figure", "figure",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.ADDRESS_OR_ARTICLE_OR_ASIDE_OR_DETAILS_OR_DIALOG_OR_DIR_OR_FIGCAPTION_OR_FIGURE_OR_FOOTER_OR_HEADER_OR_HGROUP_OR_MAIN_OR_NAV_OR_SECTION_OR_SUMMARY
-                    | SPECIAL);
-
-    public static final ElementName FECOMPOSITE = new ElementName("fecomposite",
-            "feComposite",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGFECompositeElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName IMAGE = new ElementName("image", "image",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGImageElement,
-            TreeBuilder.IMAGE);
-
-    public static final ElementName IFRAME = new ElementName("iframe", "iframe",
-            // CPPONLY: NS_NewHTMLIFrameElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.IFRAME | SPECIAL);
-
-    public static final ElementName LINE = new ElementName("line", "line",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGLineElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName MARQUEE = new ElementName("marquee",
-            "marquee",
-            // CPPONLY: NS_NewHTMLDivElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.MARQUEE_OR_APPLET | SPECIAL | SCOPING);
-
-    public static final ElementName POLYLINE = new ElementName("polyline",
-            "polyline",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGPolylineElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName PICTURE = new ElementName("picture",
-            "picture",
-            // CPPONLY: NS_NewHTMLPictureElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName SOURCE = new ElementName("source", "source",
-            // CPPONLY: NS_NewHTMLSourceElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.PARAM_OR_SOURCE_OR_TRACK);
-
-    public static final ElementName STRIKE = new ElementName("strike", "strike",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.B_OR_BIG_OR_CODE_OR_EM_OR_I_OR_S_OR_SMALL_OR_STRIKE_OR_STRONG_OR_TT_OR_U);
-
-    public static final ElementName STYLE = new ElementName("style", "style",
-            // CPPONLY: NS_NewHTMLStyleElement,
-            // CPPONLY: NS_NewSVGStyleElement,
-            TreeBuilder.STYLE | SPECIAL);
-
-    public static final ElementName TABLE = new ElementName("table", "table",
-            // CPPONLY: NS_NewHTMLTableElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.TABLE | SPECIAL | FOSTER_PARENTING | SCOPING);
-
-    public static final ElementName TITLE = new ElementName("title", "title",
-            // CPPONLY: NS_NewHTMLTitleElement,
-            // CPPONLY: NS_NewSVGTitleElement,
-            TreeBuilder.TITLE | SPECIAL | SCOPING_AS_SVG);
-
-    public static final ElementName TIME = new ElementName("time", "time",
-            // CPPONLY: NS_NewHTMLTimeElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName TEMPLATE = new ElementName("template",
-            "template",
-            // CPPONLY: NS_NewHTMLTemplateElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.TEMPLATE | SPECIAL | SCOPING);
-
-    public static final ElementName ALTGLYPHDEF = new ElementName("altglyphdef",
-            "altGlyphDef",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName GLYPHREF = new ElementName("glyphref",
-            "glyphRef",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName DIALOG = new ElementName("dialog", "dialog",
-            // CPPONLY: NS_NewHTMLDialogElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.ADDRESS_OR_ARTICLE_OR_ASIDE_OR_DETAILS_OR_DIALOG_OR_DIR_OR_FIGCAPTION_OR_FIGURE_OR_FOOTER_OR_HEADER_OR_HGROUP_OR_MAIN_OR_NAV_OR_SECTION_OR_SUMMARY
-                    | SPECIAL);
-
-    public static final ElementName FEFUNCG = new ElementName("fefuncg",
-            "feFuncG",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGFEFuncGElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName FEDIFFUSELIGHTING = new ElementName(
-            "fediffuselighting", "feDiffuseLighting",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGFEDiffuseLightingElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName FESPECULARLIGHTING = new ElementName(
-            "fespecularlighting", "feSpecularLighting",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGFESpecularLightingElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName LISTING = new ElementName("listing",
-            "listing",
-            // CPPONLY: NS_NewHTMLPreElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.PRE_OR_LISTING | SPECIAL);
-
-    public static final ElementName STRONG = new ElementName("strong", "strong",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.B_OR_BIG_OR_CODE_OR_EM_OR_I_OR_S_OR_SMALL_OR_STRIKE_OR_STRONG_OR_TT_OR_U);
-
-    public static final ElementName ALTGLYPH = new ElementName("altglyph",
-            "altGlyph",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName CLIPPATH = new ElementName("clippath",
-            "clipPath",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGClipPathElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName MGLYPH = new ElementName("mglyph", "mglyph",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.MGLYPH_OR_MALIGNMARK);
-
-    public static final ElementName MATH = new ElementName("math", "math",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.MATH);
-
-    public static final ElementName MPATH = new ElementName("mpath", "mpath",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGMPathElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName PATH = new ElementName("path", "path",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGPathElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName TH = new ElementName("th", "th",
-            // CPPONLY: NS_NewHTMLTableCellElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.TD_OR_TH | SPECIAL | SCOPING | OPTIONAL_END_TAG);
-
-    public static final ElementName SWITCH = new ElementName("switch", "switch",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGSwitchElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName TEXTPATH = new ElementName("textpath",
-            "textPath",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGTextPathElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName LI = new ElementName("li", "li",
-            // CPPONLY: NS_NewHTMLLIElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.LI | SPECIAL | OPTIONAL_END_TAG);
-
-    public static final ElementName MI = new ElementName("mi", "mi",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.MI_MO_MN_MS_MTEXT | SCOPING_AS_MATHML);
-
-    public static final ElementName LINK = new ElementName("link", "link",
-            // CPPONLY: NS_NewHTMLLinkElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.LINK_OR_BASEFONT_OR_BGSOUND | SPECIAL);
-
-    public static final ElementName MARK = new ElementName("mark", "mark",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName MALIGNMARK = new ElementName("malignmark",
-            "malignmark",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.MGLYPH_OR_MALIGNMARK);
-
-    public static final ElementName MASK = new ElementName("mask", "mask",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGMaskElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName TRACK = new ElementName("track", "track",
-            // CPPONLY: NS_NewHTMLTrackElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.PARAM_OR_SOURCE_OR_TRACK | SPECIAL);
-
-    public static final ElementName DL = new ElementName("dl", "dl",
-            // CPPONLY: NS_NewHTMLSharedListElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.UL_OR_OL_OR_DL | SPECIAL);
-
-    public static final ElementName HTML = new ElementName("html", "html",
-            // CPPONLY: NS_NewHTMLSharedElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.HTML | SPECIAL | SCOPING | OPTIONAL_END_TAG);
-
-    public static final ElementName OL = new ElementName("ol", "ol",
-            // CPPONLY: NS_NewHTMLSharedListElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.UL_OR_OL_OR_DL | SPECIAL);
-
-    public static final ElementName LABEL = new ElementName("label", "label",
-            // CPPONLY: NS_NewHTMLLabelElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName UL = new ElementName("ul", "ul",
-            // CPPONLY: NS_NewHTMLSharedListElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.UL_OR_OL_OR_DL | SPECIAL);
-
-    public static final ElementName SMALL = new ElementName("small", "small",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.B_OR_BIG_OR_CODE_OR_EM_OR_I_OR_S_OR_SMALL_OR_STRIKE_OR_STRONG_OR_TT_OR_U);
-
-    public static final ElementName SYMBOL = new ElementName("symbol", "symbol",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGSymbolElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName ALTGLYPHITEM = new ElementName(
-            "altglyphitem", "altGlyphItem",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName ANIMATETRANSFORM = new ElementName(
-            "animatetransform", "animateTransform",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGAnimateTransformElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName ACRONYM = new ElementName("acronym",
-            "acronym",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName EM = new ElementName("em", "em",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.B_OR_BIG_OR_CODE_OR_EM_OR_I_OR_S_OR_SMALL_OR_STRIKE_OR_STRONG_OR_TT_OR_U);
-
-    public static final ElementName FORM = new ElementName("form", "form",
-            // CPPONLY: NS_NewHTMLFormElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.FORM | SPECIAL);
-
-    public static final ElementName MENUITEM = new ElementName("menuitem",
-            "menuitem",
-            // CPPONLY: NS_NewHTMLMenuItemElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.MENUITEM);
-
-    public static final ElementName PARAM = new ElementName("param", "param",
-            // CPPONLY: NS_NewHTMLSharedElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.PARAM_OR_SOURCE_OR_TRACK | SPECIAL);
-
-    public static final ElementName ANIMATEMOTION = new ElementName(
-            "animatemotion", "animateMotion",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGAnimateMotionElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName BUTTON = new ElementName("button", "button",
-            // CPPONLY: NS_NewHTMLButtonElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.BUTTON | SPECIAL);
-
-    public static final ElementName CAPTION = new ElementName("caption",
-            "caption",
-            // CPPONLY: NS_NewHTMLTableCaptionElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.CAPTION | SPECIAL | SCOPING);
-
-    public static final ElementName FIGCAPTION = new ElementName("figcaption",
-            "figcaption",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.ADDRESS_OR_ARTICLE_OR_ASIDE_OR_DETAILS_OR_DIALOG_OR_DIR_OR_FIGCAPTION_OR_FIGURE_OR_FOOTER_OR_HEADER_OR_HGROUP_OR_MAIN_OR_NAV_OR_SECTION_OR_SUMMARY
-                    | SPECIAL);
-
-    public static final ElementName MN = new ElementName("mn", "mn",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.MI_MO_MN_MS_MTEXT | SCOPING_AS_MATHML);
-
-    public static final ElementName KEYGEN = new ElementName("keygen", "keygen",
-            // CPPONLY: NS_NewHTMLSpanElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.KEYGEN);
-
-    public static final ElementName MAIN = new ElementName("main", "main",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.ADDRESS_OR_ARTICLE_OR_ASIDE_OR_DETAILS_OR_DIALOG_OR_DIR_OR_FIGCAPTION_OR_FIGURE_OR_FOOTER_OR_HEADER_OR_HGROUP_OR_MAIN_OR_NAV_OR_SECTION_OR_SUMMARY
-                    | SPECIAL);
-
-    public static final ElementName OPTION = new ElementName("option", "option",
-            // CPPONLY: NS_NewHTMLOptionElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.OPTION | OPTIONAL_END_TAG);
-
-    public static final ElementName POLYGON = new ElementName("polygon",
-            "polygon",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGPolygonElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName PATTERN = new ElementName("pattern",
-            "pattern",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGPatternElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName SPAN = new ElementName("span", "span",
-            // CPPONLY: NS_NewHTMLSpanElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.RUBY_OR_SPAN_OR_SUB_OR_SUP_OR_VAR);
-
-    public static final ElementName SECTION = new ElementName("section",
-            "section",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.ADDRESS_OR_ARTICLE_OR_ASIDE_OR_DETAILS_OR_DIALOG_OR_DIR_OR_FIGCAPTION_OR_FIGURE_OR_FOOTER_OR_HEADER_OR_HGROUP_OR_MAIN_OR_NAV_OR_SECTION_OR_SUMMARY
-                    | SPECIAL);
-
-    public static final ElementName TSPAN = new ElementName("tspan", "tspan",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGTSpanElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName AUDIO = new ElementName("audio", "audio",
-            // CPPONLY: NS_NewHTMLAudioElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName MO = new ElementName("mo", "mo",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.MI_MO_MN_MS_MTEXT | SCOPING_AS_MATHML);
-
-    public static final ElementName VIDEO = new ElementName("video", "video",
-            // CPPONLY: NS_NewHTMLVideoElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName COLGROUP = new ElementName("colgroup",
-            "colgroup",
-            // CPPONLY: NS_NewHTMLTableColElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.COLGROUP | SPECIAL | OPTIONAL_END_TAG);
-
-    public static final ElementName FEDISPLACEMENTMAP = new ElementName(
-            "fedisplacementmap", "feDisplacementMap",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGFEDisplacementMapElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName HGROUP = new ElementName("hgroup", "hgroup",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.ADDRESS_OR_ARTICLE_OR_ASIDE_OR_DETAILS_OR_DIALOG_OR_DIR_OR_FIGCAPTION_OR_FIGURE_OR_FOOTER_OR_HEADER_OR_HGROUP_OR_MAIN_OR_NAV_OR_SECTION_OR_SUMMARY
-                    | SPECIAL);
-
-    public static final ElementName RP = new ElementName("rp", "rp",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.RT_OR_RP | OPTIONAL_END_TAG);
-
-    public static final ElementName OPTGROUP = new ElementName("optgroup",
-            "optgroup",
-            // CPPONLY: NS_NewHTMLOptGroupElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.OPTGROUP | OPTIONAL_END_TAG);
-
-    public static final ElementName SAMP = new ElementName("samp", "samp",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName STOP = new ElementName("stop", "stop",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGStopElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName BR = new ElementName("br", "br",
-            // CPPONLY: NS_NewHTMLBRElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.BR | SPECIAL);
-
-    public static final ElementName ABBR = new ElementName("abbr", "abbr",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName ANIMATECOLOR = new ElementName(
-            "animatecolor", "animateColor",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName CENTER = new ElementName("center", "center",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.DIV_OR_BLOCKQUOTE_OR_CENTER_OR_MENU | SPECIAL);
-
-    public static final ElementName HR = new ElementName("hr", "hr",
-            // CPPONLY: NS_NewHTMLHRElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.HR | SPECIAL);
-
-    public static final ElementName FEFUNCR = new ElementName("fefuncr",
-            "feFuncR",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGFEFuncRElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName FECOMPONENTTRANSFER = new ElementName(
-            "fecomponenttransfer", "feComponentTransfer",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGFEComponentTransferElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName FILTER = new ElementName("filter", "filter",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGFilterElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName FOOTER = new ElementName("footer", "footer",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.ADDRESS_OR_ARTICLE_OR_ASIDE_OR_DETAILS_OR_DIALOG_OR_DIR_OR_FIGCAPTION_OR_FIGURE_OR_FOOTER_OR_HEADER_OR_HGROUP_OR_MAIN_OR_NAV_OR_SECTION_OR_SUMMARY
-                    | SPECIAL);
-
-    public static final ElementName FEGAUSSIANBLUR = new ElementName(
-            "fegaussianblur", "feGaussianBlur",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGFEGaussianBlurElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName HEADER = new ElementName("header", "header",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.ADDRESS_OR_ARTICLE_OR_ASIDE_OR_DETAILS_OR_DIALOG_OR_DIR_OR_FIGCAPTION_OR_FIGURE_OR_FOOTER_OR_HEADER_OR_HGROUP_OR_MAIN_OR_NAV_OR_SECTION_OR_SUMMARY
-                    | SPECIAL);
-
-    public static final ElementName MARKER = new ElementName("marker", "marker",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGMarkerElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName METER = new ElementName("meter", "meter",
-            // CPPONLY: NS_NewHTMLMeterElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName NOBR = new ElementName("nobr", "nobr",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.NOBR);
-
-    public static final ElementName TR = new ElementName("tr", "tr",
-            // CPPONLY: NS_NewHTMLTableRowElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.TR | SPECIAL | FOSTER_PARENTING | OPTIONAL_END_TAG);
-
-    public static final ElementName ADDRESS = new ElementName("address",
-            "address",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.ADDRESS_OR_ARTICLE_OR_ASIDE_OR_DETAILS_OR_DIALOG_OR_DIR_OR_FIGCAPTION_OR_FIGURE_OR_FOOTER_OR_HEADER_OR_HGROUP_OR_MAIN_OR_NAV_OR_SECTION_OR_SUMMARY
-                    | SPECIAL);
-
-    public static final ElementName CANVAS = new ElementName("canvas", "canvas",
-            // CPPONLY: NS_NewHTMLCanvasElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName DEFS = new ElementName("defs", "defs",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGDefsElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName DETAILS = new ElementName("details",
-            "details",
-            // CPPONLY: NS_NewHTMLDetailsElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.ADDRESS_OR_ARTICLE_OR_ASIDE_OR_DETAILS_OR_DIALOG_OR_DIR_OR_FIGCAPTION_OR_FIGURE_OR_FOOTER_OR_HEADER_OR_HGROUP_OR_MAIN_OR_NAV_OR_SECTION_OR_SUMMARY
-                    | SPECIAL);
-
-    public static final ElementName MS = new ElementName("ms", "ms",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.MI_MO_MN_MS_MTEXT | SCOPING_AS_MATHML);
-
-    public static final ElementName NOFRAMES = new ElementName("noframes",
-            "noframes",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.NOFRAMES | SPECIAL);
-
-    public static final ElementName PROGRESS = new ElementName("progress",
-            "progress",
-            // CPPONLY: NS_NewHTMLProgressElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName DT = new ElementName("dt", "dt",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.DD_OR_DT | SPECIAL | OPTIONAL_END_TAG);
-
-    public static final ElementName APPLET = new ElementName("applet", "applet",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.MARQUEE_OR_APPLET | SPECIAL | SCOPING);
-
-    public static final ElementName BASEFONT = new ElementName("basefont",
-            "basefont",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.LINK_OR_BASEFONT_OR_BGSOUND | SPECIAL);
-
-    public static final ElementName CONTENT = new ElementName("content",
-            "content",
-            // CPPONLY: NS_NewHTMLContentElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName DATALIST = new ElementName("datalist",
-            "datalist",
-            // CPPONLY: NS_NewHTMLDataListElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName FOREIGNOBJECT = new ElementName(
-            "foreignobject", "foreignObject",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGForeignObjectElement,
-            TreeBuilder.FOREIGNOBJECT_OR_DESC | SCOPING_AS_SVG);
-
-    public static final ElementName FIELDSET = new ElementName("fieldset",
-            "fieldset",
-            // CPPONLY: NS_NewHTMLFieldSetElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.FIELDSET | SPECIAL);
-
-    public static final ElementName FRAMESET = new ElementName("frameset",
-            "frameset",
-            // CPPONLY: NS_NewHTMLFrameSetElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.FRAMESET | SPECIAL);
-
-    public static final ElementName FEOFFSET = new ElementName("feoffset",
-            "feOffset",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGFEOffsetElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName FESPOTLIGHT = new ElementName("fespotlight",
-            "feSpotLight",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGFESpotLightElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName FEPOINTLIGHT = new ElementName(
-            "fepointlight", "fePointLight",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGFEPointLightElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName FEDISTANTLIGHT = new ElementName(
-            "fedistantlight", "feDistantLight",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGFEDistantLightElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName FONT = new ElementName("font", "font",
-            // CPPONLY: NS_NewHTMLFontElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.FONT);
-
-    public static final ElementName INPUT = new ElementName("input", "input",
-            // CPPONLY: NS_NewHTMLInputElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.INPUT | SPECIAL);
-
-    public static final ElementName LINEARGRADIENT = new ElementName(
-            "lineargradient", "linearGradient",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGLinearGradientElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName MTEXT = new ElementName("mtext", "mtext",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.MI_MO_MN_MS_MTEXT | SCOPING_AS_MATHML);
-
-    public static final ElementName NOSCRIPT = new ElementName("noscript",
-            "noscript",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.NOSCRIPT | SPECIAL);
-
-    public static final ElementName RT = new ElementName("rt", "rt",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.RT_OR_RP | OPTIONAL_END_TAG);
-
-    public static final ElementName OBJECT = new ElementName("object", "object",
-            // CPPONLY: NS_NewHTMLObjectElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.OBJECT | SPECIAL | SCOPING);
-
-    public static final ElementName OUTPUT = new ElementName("output", "output",
-            // CPPONLY: NS_NewHTMLOutputElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.OUTPUT);
-
-    public static final ElementName PLAINTEXT = new ElementName("plaintext",
-            "plaintext",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.PLAINTEXT | SPECIAL);
-
-    public static final ElementName TT = new ElementName("tt", "tt",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.B_OR_BIG_OR_CODE_OR_EM_OR_I_OR_S_OR_SMALL_OR_STRIKE_OR_STRONG_OR_TT_OR_U);
-
-    public static final ElementName RECT = new ElementName("rect", "rect",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGRectElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName RADIALGRADIENT = new ElementName(
-            "radialgradient", "radialGradient",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGRadialGradientElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName SELECT = new ElementName("select", "select",
-            // CPPONLY: NS_NewHTMLSelectElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.SELECT | SPECIAL);
-
-    public static final ElementName SCRIPT = new ElementName("script", "script",
-            // CPPONLY: NS_NewHTMLScriptElement,
-            // CPPONLY: NS_NewSVGScriptElement,
-            TreeBuilder.SCRIPT | SPECIAL);
-
-    public static final ElementName TFOOT = new ElementName("tfoot", "tfoot",
-            // CPPONLY: NS_NewHTMLTableSectionElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.TBODY_OR_THEAD_OR_TFOOT | SPECIAL | FOSTER_PARENTING
-                    | OPTIONAL_END_TAG);
-
-    public static final ElementName TEXT = new ElementName("text", "text",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGTextElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName MENU = new ElementName("menu", "menu",
-            // CPPONLY: NS_NewHTMLMenuElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.DIV_OR_BLOCKQUOTE_OR_CENTER_OR_MENU | SPECIAL);
-
-    public static final ElementName FEDROPSHADOW = new ElementName(
-            "fedropshadow", "feDropShadow",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGFEDropShadowElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName SHADOW = new ElementName("shadow", "shadow",
-            // CPPONLY: NS_NewHTMLShadowElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName VIEW = new ElementName("view", "view",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGViewElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName FECOLORMATRIX = new ElementName(
-            "fecolormatrix", "feColorMatrix",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGFEColorMatrixElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName FECONVOLVEMATRIX = new ElementName(
-            "feconvolvematrix", "feConvolveMatrix",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGFEConvolveMatrixElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName BODY = new ElementName("body", "body",
-            // CPPONLY: NS_NewHTMLBodyElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.BODY | SPECIAL | OPTIONAL_END_TAG);
-
-    public static final ElementName FEMORPHOLOGY = new ElementName(
-            "femorphology", "feMorphology",
-            // CPPONLY: NS_NewHTMLUnknownElement,
-            // CPPONLY: NS_NewSVGFEMorphologyElement,
-            TreeBuilder.OTHER);
-
-    public static final ElementName RUBY = new ElementName("ruby", "ruby",
-            // CPPONLY: NS_NewHTMLElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.RUBY_OR_SPAN_OR_SUB_OR_SUP_OR_VAR);
-
-    public static final ElementName SUMMARY = new ElementName("summary",
-            "summary",
-            // CPPONLY: NS_NewHTMLSummaryElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.ADDRESS_OR_ARTICLE_OR_ASIDE_OR_DETAILS_OR_DIALOG_OR_DIR_OR_FIGCAPTION_OR_FIGURE_OR_FOOTER_OR_HEADER_OR_HGROUP_OR_MAIN_OR_NAV_OR_SECTION_OR_SUMMARY
-                    | SPECIAL);
-
-    public static final ElementName TBODY = new ElementName("tbody", "tbody",
-            // CPPONLY: NS_NewHTMLTableSectionElement,
-            // CPPONLY: NS_NewSVGUnknownElement,
-            TreeBuilder.TBODY_OR_THEAD_OR_TFOOT | SPECIAL | FOSTER_PARENTING
-                    | OPTIONAL_END_TAG);
-
-    private final static @NoLength ElementName[] ELEMENT_NAMES = { MN, ELLIPSE,
-            FRAMESET, H2, MGLYPH, NOBR, RADIALGRADIENT, RTC, EMBED, STRIKE, OL,
-            OPTGROUP, PROGRESS, MTEXT, VIEW, IMG, WBR, METADATA, ASIDE,
-            FECOMPOSITE, DIALOG, MI, EM, TSPAN, FEFUNCR, DEFS, CONTENT,
-            FEDISTANTLIGHT, OUTPUT, TEXT, FEMORPHOLOGY, DEL, NAV, SET, Q, H6,
-            RB, LEGEND, BLOCKQUOTE, FEMERGE, MARQUEE, TIME, LISTING, TH, MASK,
-            SYMBOL, ANIMATEMOTION, POLYGON, COLGROUP, ABBR, FEGAUSSIANBLUR,
-            ADDRESS, MS, APPLET, FOREIGNOBJECT, FESPOTLIGHT, INPUT, RT, TT,
-            SCRIPT, FEDROPSHADOW, FECONVOLVEMATRIX, SUMMARY, BDO, DIR, KBD, A,
-            SVG, VAR, I, U, H4, DATA, TEXTAREA, DD, FEFLOOD, TD, ANIMATE,
-            CIRCLE, FEMERGENODE, FRAME, IFRAME, PICTURE, TABLE, ALTGLYPHDEF,
-            FEDIFFUSELIGHTING, ALTGLYPH, MPATH, TEXTPATH, MARK, DL, UL,
-            ANIMATETRANSFORM, MENUITEM, CAPTION, MAIN, SPAN, MO, HGROUP, STOP,
-            CENTER, FILTER, MARKER, TR, CANVAS, DETAILS, NOFRAMES, DT, BASEFONT,
-            DATALIST, FIELDSET, FEOFFSET, FEPOINTLIGHT, FONT, LINEARGRADIENT,
-            NOSCRIPT, OBJECT, PLAINTEXT, RECT, SELECT, TFOOT, MENU, SHADOW,
-            FECOLORMATRIX, BODY, RUBY, TBODY, BIG, COL, DFN, DIV, INS, MAP, PRE,
-            B, SUB, SUP, USE, G, XMP, P, S, H1, H3, H5, AREA, FEFUNCA, META,
-            FEFUNCB, DESC, BGSOUND, FEBLEND, HEAD, NOEMBED, THEAD, ARTICLE,
-            BASE, CODE, CITE, FETURBULENCE, FEIMAGE, FETILE, FIGURE, IMAGE,
-            LINE, POLYLINE, SOURCE, STYLE, TITLE, TEMPLATE, GLYPHREF, FEFUNCG,
-            FESPECULARLIGHTING, STRONG, CLIPPATH, MATH, PATH, SWITCH, LI, LINK,
-            MALIGNMARK, TRACK, HTML, LABEL, SMALL, ALTGLYPHITEM, ACRONYM, FORM,
-            PARAM, BUTTON, FIGCAPTION, KEYGEN, OPTION, PATTERN, SECTION, AUDIO,
-            VIDEO, FEDISPLACEMENTMAP, RP, SAMP, BR, ANIMATECOLOR, HR,
-            FECOMPONENTTRANSFER, FOOTER, HEADER, METER, };
-
-    private final static int[] ELEMENT_HASHES = { 1902641154, 1749395095,
-            2001349720, 893386754, 1803876550, 1971938532, 2007781534, 59821379,
-            1732381397, 1756600614, 1870135298, 1939219752, 1990037800,
-            2005324101, 2060065124, 55104723, 62450211, 1686489160, 1747048757,
-            1749932347, 1782357526, 1818755074, 1881669634, 1907959605,
-            1967760215, 1983533124, 1999917383, 2001392798, 2006329158,
-            2008994116, 2085266636, 52485715, 57733651, 60354131, 67633153,
-            960495618, 1703936002, 1736200310, 1747838298, 1749723735,
-            1753362711, 1757157700, 1786534215, 1805647874, 1854245076,
-            1874102998, 1898223949, 1906087319, 1932928296, 1965115924,
-            1968053806, 1982173479, 1986527234, 1998724870, 2001309869,
-            2001392795, 2003183333, 2005925890, 2006974466, 2008340774,
-            2051837468, 2068523856, 2092255447, 51438659, 52488851, 56151587,
-            59244545, 60347747, 61925907, 63438849, 69730305, 926941186,
-            1681770564, 1689922072, 1730150402, 1733076167, 1738539010,
-            1747306711, 1748225318, 1749673195, 1749813541, 1751386406,
-            1755148615, 1757137429, 1763839627, 1783388497, 1797585096,
-            1803929861, 1807599880, 1854228692, 1864368130, 1873281026,
-            1881498736, 1887579800, 1899272519, 1904412884, 1907435316,
-            1919418370, 1935549734, 1941221172, 1966223078, 1967795910,
-            1971461414, 1973420034, 1982935782, 1983633431, 1988763672,
-            1998585858, 1999397992, 2000525512, 2001349704, 2001349736,
-            2001392796, 2001495140, 2004635806, 2005719336, 2006028454,
-            2006896969, 2007601444, 2008125638, 2008851557, 2021937364,
-            2058653206, 2068523853, 2083120164, 2091479332, 2092557349,
-            51434643, 51961587, 52486755, 52490899, 55110883, 57206291,
-            58773795, 59768833, 60345171, 60352339, 61395251, 62390273,
-            62973651, 67108865, 68681729, 876609538, 910163970, 943718402,
-            1679960596, 1682547543, 1686491348, 1699324759, 1715310660,
-            1730965751, 1733054663, 1733890180, 1737099991, 1740181637,
-            1747176599, 1747814436, 1748100148, 1748359220, 1749656156,
-            1749715159, 1749801286, 1749905526, 1751288021, 1752979652,
-            1755076808, 1756474198, 1756625221, 1757146773, 1757268168,
-            1766992520, 1783210839, 1783388498, 1790207270, 1798686984,
-            1803929812, 1805502724, 1806806678, 1818230786, 1853642948,
-            1854228698, 1857653029, 1868312196, 1870268949, 1874053333,
-            1881288348, 1881613047, 1884120164, 1889085973, 1898753862,
-            1900845386, 1903302038, 1905563974, 1906135367, 1907661127,
-            1914900309, 1925844629, 1934172497, 1938817026, 1941178676,
-            1963982850, 1965334268, 1967128578, 1967788867, 1967795958,
-            1968836118, 1971465813, };
-
+public static final ElementName BIG = new ElementName("big", "big", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.B_OR_BIG_OR_CODE_OR_EM_OR_I_OR_S_OR_SMALL_OR_STRIKE_OR_STRONG_OR_TT_OR_U);
+public static final ElementName BDO = new ElementName("bdo", "bdo", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.OTHER);
+public static final ElementName COL = new ElementName("col", "col", 
+// CPPONLY: NS_NewHTMLTableColElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.COL | SPECIAL);
+public static final ElementName DEL = new ElementName("del", "del", 
+// CPPONLY: NS_NewHTMLModElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.OTHER);
+public static final ElementName DFN = new ElementName("dfn", "dfn", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.OTHER);
+public static final ElementName DIR = new ElementName("dir", "dir", 
+// CPPONLY: NS_NewHTMLSharedElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.ADDRESS_OR_ARTICLE_OR_ASIDE_OR_DETAILS_OR_DIALOG_OR_DIR_OR_FIGCAPTION_OR_FIGURE_OR_FOOTER_OR_HEADER_OR_HGROUP_OR_MAIN_OR_NAV_OR_SECTION_OR_SUMMARY | SPECIAL);
+public static final ElementName DIV = new ElementName("div", "div", 
+// CPPONLY: NS_NewHTMLDivElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.DIV_OR_BLOCKQUOTE_OR_CENTER_OR_MENU | SPECIAL);
+public static final ElementName IMG = new ElementName("img", "img", 
+// CPPONLY: NS_NewHTMLImageElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.IMG | SPECIAL);
+public static final ElementName INS = new ElementName("ins", "ins", 
+// CPPONLY: NS_NewHTMLModElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.OTHER);
+public static final ElementName KBD = new ElementName("kbd", "kbd", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.OTHER);
+public static final ElementName MAP = new ElementName("map", "map", 
+// CPPONLY: NS_NewHTMLMapElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.OTHER);
+public static final ElementName NAV = new ElementName("nav", "nav", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.ADDRESS_OR_ARTICLE_OR_ASIDE_OR_DETAILS_OR_DIALOG_OR_DIR_OR_FIGCAPTION_OR_FIGURE_OR_FOOTER_OR_HEADER_OR_HGROUP_OR_MAIN_OR_NAV_OR_SECTION_OR_SUMMARY | SPECIAL);
+public static final ElementName PRE = new ElementName("pre", "pre", 
+// CPPONLY: NS_NewHTMLPreElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.PRE_OR_LISTING | SPECIAL);
+public static final ElementName A = new ElementName("a", "a", 
+// CPPONLY: NS_NewHTMLAnchorElement,
+// CPPONLY: NS_NewSVGAElement, 
+TreeBuilder.A);
+public static final ElementName B = new ElementName("b", "b", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.B_OR_BIG_OR_CODE_OR_EM_OR_I_OR_S_OR_SMALL_OR_STRIKE_OR_STRONG_OR_TT_OR_U);
+public static final ElementName RTC = new ElementName("rtc", "rtc", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.RB_OR_RTC | OPTIONAL_END_TAG);
+public static final ElementName SUB = new ElementName("sub", "sub", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.RUBY_OR_SPAN_OR_SUB_OR_SUP_OR_VAR);
+public static final ElementName SVG = new ElementName("svg", "svg", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGSVGElement, 
+TreeBuilder.SVG);
+public static final ElementName SUP = new ElementName("sup", "sup", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.RUBY_OR_SPAN_OR_SUB_OR_SUP_OR_VAR);
+public static final ElementName SET = new ElementName("set", "set", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGSetElement, 
+TreeBuilder.OTHER);
+public static final ElementName USE = new ElementName("use", "use", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGUseElement, 
+TreeBuilder.OTHER);
+public static final ElementName VAR = new ElementName("var", "var", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.RUBY_OR_SPAN_OR_SUB_OR_SUP_OR_VAR);
+public static final ElementName G = new ElementName("g", "g", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGGElement, 
+TreeBuilder.OTHER);
+public static final ElementName WBR = new ElementName("wbr", "wbr", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.AREA_OR_WBR | SPECIAL);
+public static final ElementName XMP = new ElementName("xmp", "xmp", 
+// CPPONLY: NS_NewHTMLPreElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.XMP | SPECIAL);
+public static final ElementName I = new ElementName("i", "i", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.B_OR_BIG_OR_CODE_OR_EM_OR_I_OR_S_OR_SMALL_OR_STRIKE_OR_STRONG_OR_TT_OR_U);
+public static final ElementName P = new ElementName("p", "p", 
+// CPPONLY: NS_NewHTMLParagraphElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.P | SPECIAL | OPTIONAL_END_TAG);
+public static final ElementName Q = new ElementName("q", "q", 
+// CPPONLY: NS_NewHTMLSharedElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.OTHER);
+public static final ElementName S = new ElementName("s", "s", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.B_OR_BIG_OR_CODE_OR_EM_OR_I_OR_S_OR_SMALL_OR_STRIKE_OR_STRONG_OR_TT_OR_U);
+public static final ElementName U = new ElementName("u", "u", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.B_OR_BIG_OR_CODE_OR_EM_OR_I_OR_S_OR_SMALL_OR_STRIKE_OR_STRONG_OR_TT_OR_U);
+public static final ElementName H1 = new ElementName("h1", "h1", 
+// CPPONLY: NS_NewHTMLHeadingElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.H1_OR_H2_OR_H3_OR_H4_OR_H5_OR_H6 | SPECIAL);
+public static final ElementName H2 = new ElementName("h2", "h2", 
+// CPPONLY: NS_NewHTMLHeadingElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.H1_OR_H2_OR_H3_OR_H4_OR_H5_OR_H6 | SPECIAL);
+public static final ElementName H3 = new ElementName("h3", "h3", 
+// CPPONLY: NS_NewHTMLHeadingElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.H1_OR_H2_OR_H3_OR_H4_OR_H5_OR_H6 | SPECIAL);
+public static final ElementName H4 = new ElementName("h4", "h4", 
+// CPPONLY: NS_NewHTMLHeadingElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.H1_OR_H2_OR_H3_OR_H4_OR_H5_OR_H6 | SPECIAL);
+public static final ElementName H5 = new ElementName("h5", "h5", 
+// CPPONLY: NS_NewHTMLHeadingElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.H1_OR_H2_OR_H3_OR_H4_OR_H5_OR_H6 | SPECIAL);
+public static final ElementName H6 = new ElementName("h6", "h6", 
+// CPPONLY: NS_NewHTMLHeadingElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.H1_OR_H2_OR_H3_OR_H4_OR_H5_OR_H6 | SPECIAL);
+public static final ElementName AREA = new ElementName("area", "area", 
+// CPPONLY: NS_NewHTMLAreaElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.AREA_OR_WBR | SPECIAL);
+public static final ElementName DATA = new ElementName("data", "data", 
+// CPPONLY: NS_NewHTMLDataElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.OTHER);
+public static final ElementName FEFUNCA = new ElementName("fefunca", "feFuncA", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGFEFuncAElement, 
+TreeBuilder.OTHER);
+public static final ElementName METADATA = new ElementName("metadata", "metadata", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGMetadataElement, 
+TreeBuilder.OTHER);
+public static final ElementName META = new ElementName("meta", "meta", 
+// CPPONLY: NS_NewHTMLMetaElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.META | SPECIAL);
+public static final ElementName TEXTAREA = new ElementName("textarea", "textarea", 
+// CPPONLY: NS_NewHTMLTextAreaElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.TEXTAREA | SPECIAL);
+public static final ElementName FEFUNCB = new ElementName("fefuncb", "feFuncB", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGFEFuncBElement, 
+TreeBuilder.OTHER);
+public static final ElementName RB = new ElementName("rb", "rb", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.RB_OR_RTC | OPTIONAL_END_TAG);
+public static final ElementName DESC = new ElementName("desc", "desc", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGDescElement, 
+TreeBuilder.FOREIGNOBJECT_OR_DESC | SCOPING_AS_SVG);
+public static final ElementName DD = new ElementName("dd", "dd", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.DD_OR_DT | SPECIAL | OPTIONAL_END_TAG);
+public static final ElementName BGSOUND = new ElementName("bgsound", "bgsound", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.LINK_OR_BASEFONT_OR_BGSOUND | SPECIAL);
+public static final ElementName EMBED = new ElementName("embed", "embed", 
+// CPPONLY: NS_NewHTMLEmbedElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.EMBED | SPECIAL);
+public static final ElementName FEBLEND = new ElementName("feblend", "feBlend", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGFEBlendElement, 
+TreeBuilder.OTHER);
+public static final ElementName FEFLOOD = new ElementName("feflood", "feFlood", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGFEFloodElement, 
+TreeBuilder.OTHER);
+public static final ElementName HEAD = new ElementName("head", "head", 
+// CPPONLY: NS_NewHTMLSharedElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.HEAD | SPECIAL | OPTIONAL_END_TAG);
+public static final ElementName LEGEND = new ElementName("legend", "legend", 
+// CPPONLY: NS_NewHTMLLegendElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.OTHER);
+public static final ElementName NOEMBED = new ElementName("noembed", "noembed", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.NOEMBED | SPECIAL);
+public static final ElementName TD = new ElementName("td", "td", 
+// CPPONLY: NS_NewHTMLTableCellElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.TD_OR_TH | SPECIAL | SCOPING | OPTIONAL_END_TAG);
+public static final ElementName THEAD = new ElementName("thead", "thead", 
+// CPPONLY: NS_NewHTMLTableSectionElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.TBODY_OR_THEAD_OR_TFOOT | SPECIAL | FOSTER_PARENTING | OPTIONAL_END_TAG);
+public static final ElementName ASIDE = new ElementName("aside", "aside", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.ADDRESS_OR_ARTICLE_OR_ASIDE_OR_DETAILS_OR_DIALOG_OR_DIR_OR_FIGCAPTION_OR_FIGURE_OR_FOOTER_OR_HEADER_OR_HGROUP_OR_MAIN_OR_NAV_OR_SECTION_OR_SUMMARY | SPECIAL);
+public static final ElementName ARTICLE = new ElementName("article", "article", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.ADDRESS_OR_ARTICLE_OR_ASIDE_OR_DETAILS_OR_DIALOG_OR_DIR_OR_FIGCAPTION_OR_FIGURE_OR_FOOTER_OR_HEADER_OR_HGROUP_OR_MAIN_OR_NAV_OR_SECTION_OR_SUMMARY | SPECIAL);
+public static final ElementName ANIMATE = new ElementName("animate", "animate", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGAnimateElement, 
+TreeBuilder.OTHER);
+public static final ElementName BASE = new ElementName("base", "base", 
+// CPPONLY: NS_NewHTMLSharedElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.BASE | SPECIAL);
+public static final ElementName BLOCKQUOTE = new ElementName("blockquote", "blockquote", 
+// CPPONLY: NS_NewHTMLSharedElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.DIV_OR_BLOCKQUOTE_OR_CENTER_OR_MENU | SPECIAL);
+public static final ElementName CODE = new ElementName("code", "code", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.B_OR_BIG_OR_CODE_OR_EM_OR_I_OR_S_OR_SMALL_OR_STRIKE_OR_STRONG_OR_TT_OR_U);
+public static final ElementName CIRCLE = new ElementName("circle", "circle", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGCircleElement, 
+TreeBuilder.OTHER);
+public static final ElementName CITE = new ElementName("cite", "cite", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.OTHER);
+public static final ElementName ELLIPSE = new ElementName("ellipse", "ellipse", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGEllipseElement, 
+TreeBuilder.OTHER);
+public static final ElementName FETURBULENCE = new ElementName("feturbulence", "feTurbulence", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGFETurbulenceElement, 
+TreeBuilder.OTHER);
+public static final ElementName FEMERGENODE = new ElementName("femergenode", "feMergeNode", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGFEMergeNodeElement, 
+TreeBuilder.OTHER);
+public static final ElementName FEIMAGE = new ElementName("feimage", "feImage", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGFEImageElement, 
+TreeBuilder.OTHER);
+public static final ElementName FEMERGE = new ElementName("femerge", "feMerge", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGFEMergeElement, 
+TreeBuilder.OTHER);
+public static final ElementName FETILE = new ElementName("fetile", "feTile", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGFETileElement, 
+TreeBuilder.OTHER);
+public static final ElementName FRAME = new ElementName("frame", "frame", 
+// CPPONLY: NS_NewHTMLFrameElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.FRAME | SPECIAL);
+public static final ElementName FIGURE = new ElementName("figure", "figure", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.ADDRESS_OR_ARTICLE_OR_ASIDE_OR_DETAILS_OR_DIALOG_OR_DIR_OR_FIGCAPTION_OR_FIGURE_OR_FOOTER_OR_HEADER_OR_HGROUP_OR_MAIN_OR_NAV_OR_SECTION_OR_SUMMARY | SPECIAL);
+public static final ElementName FECOMPOSITE = new ElementName("fecomposite", "feComposite", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGFECompositeElement, 
+TreeBuilder.OTHER);
+public static final ElementName IMAGE = new ElementName("image", "image", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGImageElement, 
+TreeBuilder.IMAGE);
+public static final ElementName IFRAME = new ElementName("iframe", "iframe", 
+// CPPONLY: NS_NewHTMLIFrameElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.IFRAME | SPECIAL);
+public static final ElementName LINE = new ElementName("line", "line", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGLineElement, 
+TreeBuilder.OTHER);
+public static final ElementName MARQUEE = new ElementName("marquee", "marquee", 
+// CPPONLY: NS_NewHTMLDivElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.MARQUEE_OR_APPLET | SPECIAL | SCOPING);
+public static final ElementName POLYLINE = new ElementName("polyline", "polyline", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGPolylineElement, 
+TreeBuilder.OTHER);
+public static final ElementName PICTURE = new ElementName("picture", "picture", 
+// CPPONLY: NS_NewHTMLPictureElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.OTHER);
+public static final ElementName SOURCE = new ElementName("source", "source", 
+// CPPONLY: NS_NewHTMLSourceElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.PARAM_OR_SOURCE_OR_TRACK);
+public static final ElementName STRIKE = new ElementName("strike", "strike", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.B_OR_BIG_OR_CODE_OR_EM_OR_I_OR_S_OR_SMALL_OR_STRIKE_OR_STRONG_OR_TT_OR_U);
+public static final ElementName STYLE = new ElementName("style", "style", 
+// CPPONLY: NS_NewHTMLStyleElement,
+// CPPONLY: NS_NewSVGStyleElement, 
+TreeBuilder.STYLE | SPECIAL);
+public static final ElementName TABLE = new ElementName("table", "table", 
+// CPPONLY: NS_NewHTMLTableElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.TABLE | SPECIAL | FOSTER_PARENTING | SCOPING);
+public static final ElementName TITLE = new ElementName("title", "title", 
+// CPPONLY: NS_NewHTMLTitleElement,
+// CPPONLY: NS_NewSVGTitleElement, 
+TreeBuilder.TITLE | SPECIAL | SCOPING_AS_SVG);
+public static final ElementName TIME = new ElementName("time", "time", 
+// CPPONLY: NS_NewHTMLTimeElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.OTHER);
+public static final ElementName TEMPLATE = new ElementName("template", "template", 
+// CPPONLY: NS_NewHTMLTemplateElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.TEMPLATE | SPECIAL | SCOPING);
+public static final ElementName ALTGLYPHDEF = new ElementName("altglyphdef", "altGlyphDef", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.OTHER);
+public static final ElementName GLYPHREF = new ElementName("glyphref", "glyphRef", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.OTHER);
+public static final ElementName DIALOG = new ElementName("dialog", "dialog", 
+// CPPONLY: NS_NewHTMLDialogElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.ADDRESS_OR_ARTICLE_OR_ASIDE_OR_DETAILS_OR_DIALOG_OR_DIR_OR_FIGCAPTION_OR_FIGURE_OR_FOOTER_OR_HEADER_OR_HGROUP_OR_MAIN_OR_NAV_OR_SECTION_OR_SUMMARY | SPECIAL);
+public static final ElementName FEFUNCG = new ElementName("fefuncg", "feFuncG", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGFEFuncGElement, 
+TreeBuilder.OTHER);
+public static final ElementName FEDIFFUSELIGHTING = new ElementName("fediffuselighting", "feDiffuseLighting", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGFEDiffuseLightingElement, 
+TreeBuilder.OTHER);
+public static final ElementName FESPECULARLIGHTING = new ElementName("fespecularlighting", "feSpecularLighting", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGFESpecularLightingElement, 
+TreeBuilder.OTHER);
+public static final ElementName LISTING = new ElementName("listing", "listing", 
+// CPPONLY: NS_NewHTMLPreElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.PRE_OR_LISTING | SPECIAL);
+public static final ElementName STRONG = new ElementName("strong", "strong", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.B_OR_BIG_OR_CODE_OR_EM_OR_I_OR_S_OR_SMALL_OR_STRIKE_OR_STRONG_OR_TT_OR_U);
+public static final ElementName ALTGLYPH = new ElementName("altglyph", "altGlyph", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.OTHER);
+public static final ElementName CLIPPATH = new ElementName("clippath", "clipPath", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGClipPathElement, 
+TreeBuilder.OTHER);
+public static final ElementName MGLYPH = new ElementName("mglyph", "mglyph", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.MGLYPH_OR_MALIGNMARK);
+public static final ElementName MATH = new ElementName("math", "math", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.MATH);
+public static final ElementName MPATH = new ElementName("mpath", "mpath", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGMPathElement, 
+TreeBuilder.OTHER);
+public static final ElementName PATH = new ElementName("path", "path", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGPathElement, 
+TreeBuilder.OTHER);
+public static final ElementName TH = new ElementName("th", "th", 
+// CPPONLY: NS_NewHTMLTableCellElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.TD_OR_TH | SPECIAL | SCOPING | OPTIONAL_END_TAG);
+public static final ElementName SWITCH = new ElementName("switch", "switch", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGSwitchElement, 
+TreeBuilder.OTHER);
+public static final ElementName TEXTPATH = new ElementName("textpath", "textPath", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGTextPathElement, 
+TreeBuilder.OTHER);
+public static final ElementName LI = new ElementName("li", "li", 
+// CPPONLY: NS_NewHTMLLIElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.LI | SPECIAL | OPTIONAL_END_TAG);
+public static final ElementName MI = new ElementName("mi", "mi", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.MI_MO_MN_MS_MTEXT | SCOPING_AS_MATHML);
+public static final ElementName LINK = new ElementName("link", "link", 
+// CPPONLY: NS_NewHTMLLinkElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.LINK_OR_BASEFONT_OR_BGSOUND | SPECIAL);
+public static final ElementName MARK = new ElementName("mark", "mark", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.OTHER);
+public static final ElementName MALIGNMARK = new ElementName("malignmark", "malignmark", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.MGLYPH_OR_MALIGNMARK);
+public static final ElementName MASK = new ElementName("mask", "mask", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGMaskElement, 
+TreeBuilder.OTHER);
+public static final ElementName TRACK = new ElementName("track", "track", 
+// CPPONLY: NS_NewHTMLTrackElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.PARAM_OR_SOURCE_OR_TRACK | SPECIAL);
+public static final ElementName DL = new ElementName("dl", "dl", 
+// CPPONLY: NS_NewHTMLSharedListElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.UL_OR_OL_OR_DL | SPECIAL);
+public static final ElementName HTML = new ElementName("html", "html", 
+// CPPONLY: NS_NewHTMLSharedElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.HTML | SPECIAL | SCOPING | OPTIONAL_END_TAG);
+public static final ElementName OL = new ElementName("ol", "ol", 
+// CPPONLY: NS_NewHTMLSharedListElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.UL_OR_OL_OR_DL | SPECIAL);
+public static final ElementName LABEL = new ElementName("label", "label", 
+// CPPONLY: NS_NewHTMLLabelElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.OTHER);
+public static final ElementName UL = new ElementName("ul", "ul", 
+// CPPONLY: NS_NewHTMLSharedListElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.UL_OR_OL_OR_DL | SPECIAL);
+public static final ElementName SMALL = new ElementName("small", "small", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.B_OR_BIG_OR_CODE_OR_EM_OR_I_OR_S_OR_SMALL_OR_STRIKE_OR_STRONG_OR_TT_OR_U);
+public static final ElementName SYMBOL = new ElementName("symbol", "symbol", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGSymbolElement, 
+TreeBuilder.OTHER);
+public static final ElementName ALTGLYPHITEM = new ElementName("altglyphitem", "altGlyphItem", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.OTHER);
+public static final ElementName ANIMATETRANSFORM = new ElementName("animatetransform", "animateTransform", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGAnimateTransformElement, 
+TreeBuilder.OTHER);
+public static final ElementName ACRONYM = new ElementName("acronym", "acronym", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.OTHER);
+public static final ElementName EM = new ElementName("em", "em", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.B_OR_BIG_OR_CODE_OR_EM_OR_I_OR_S_OR_SMALL_OR_STRIKE_OR_STRONG_OR_TT_OR_U);
+public static final ElementName FORM = new ElementName("form", "form", 
+// CPPONLY: NS_NewHTMLFormElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.FORM | SPECIAL);
+public static final ElementName MENUITEM = new ElementName("menuitem", "menuitem", 
+// CPPONLY: NS_NewHTMLMenuItemElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.MENUITEM);
+public static final ElementName PARAM = new ElementName("param", "param", 
+// CPPONLY: NS_NewHTMLSharedElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.PARAM_OR_SOURCE_OR_TRACK | SPECIAL);
+public static final ElementName ANIMATEMOTION = new ElementName("animatemotion", "animateMotion", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGAnimateMotionElement, 
+TreeBuilder.OTHER);
+public static final ElementName BUTTON = new ElementName("button", "button", 
+// CPPONLY: NS_NewHTMLButtonElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.BUTTON | SPECIAL);
+public static final ElementName CAPTION = new ElementName("caption", "caption", 
+// CPPONLY: NS_NewHTMLTableCaptionElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.CAPTION | SPECIAL | SCOPING);
+public static final ElementName FIGCAPTION = new ElementName("figcaption", "figcaption", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.ADDRESS_OR_ARTICLE_OR_ASIDE_OR_DETAILS_OR_DIALOG_OR_DIR_OR_FIGCAPTION_OR_FIGURE_OR_FOOTER_OR_HEADER_OR_HGROUP_OR_MAIN_OR_NAV_OR_SECTION_OR_SUMMARY | SPECIAL);
+public static final ElementName MN = new ElementName("mn", "mn", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.MI_MO_MN_MS_MTEXT | SCOPING_AS_MATHML);
+public static final ElementName KEYGEN = new ElementName("keygen", "keygen", 
+// CPPONLY: NS_NewHTMLSpanElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.KEYGEN);
+public static final ElementName MAIN = new ElementName("main", "main", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.ADDRESS_OR_ARTICLE_OR_ASIDE_OR_DETAILS_OR_DIALOG_OR_DIR_OR_FIGCAPTION_OR_FIGURE_OR_FOOTER_OR_HEADER_OR_HGROUP_OR_MAIN_OR_NAV_OR_SECTION_OR_SUMMARY | SPECIAL);
+public static final ElementName OPTION = new ElementName("option", "option", 
+// CPPONLY: NS_NewHTMLOptionElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.OPTION | OPTIONAL_END_TAG);
+public static final ElementName POLYGON = new ElementName("polygon", "polygon", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGPolygonElement, 
+TreeBuilder.OTHER);
+public static final ElementName PATTERN = new ElementName("pattern", "pattern", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGPatternElement, 
+TreeBuilder.OTHER);
+public static final ElementName SPAN = new ElementName("span", "span", 
+// CPPONLY: NS_NewHTMLSpanElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.RUBY_OR_SPAN_OR_SUB_OR_SUP_OR_VAR);
+public static final ElementName SECTION = new ElementName("section", "section", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.ADDRESS_OR_ARTICLE_OR_ASIDE_OR_DETAILS_OR_DIALOG_OR_DIR_OR_FIGCAPTION_OR_FIGURE_OR_FOOTER_OR_HEADER_OR_HGROUP_OR_MAIN_OR_NAV_OR_SECTION_OR_SUMMARY | SPECIAL);
+public static final ElementName TSPAN = new ElementName("tspan", "tspan", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGTSpanElement, 
+TreeBuilder.OTHER);
+public static final ElementName AUDIO = new ElementName("audio", "audio", 
+// CPPONLY: NS_NewHTMLAudioElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.OTHER);
+public static final ElementName MO = new ElementName("mo", "mo", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.MI_MO_MN_MS_MTEXT | SCOPING_AS_MATHML);
+public static final ElementName VIDEO = new ElementName("video", "video", 
+// CPPONLY: NS_NewHTMLVideoElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.OTHER);
+public static final ElementName COLGROUP = new ElementName("colgroup", "colgroup", 
+// CPPONLY: NS_NewHTMLTableColElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.COLGROUP | SPECIAL | OPTIONAL_END_TAG);
+public static final ElementName FEDISPLACEMENTMAP = new ElementName("fedisplacementmap", "feDisplacementMap", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGFEDisplacementMapElement, 
+TreeBuilder.OTHER);
+public static final ElementName HGROUP = new ElementName("hgroup", "hgroup", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.ADDRESS_OR_ARTICLE_OR_ASIDE_OR_DETAILS_OR_DIALOG_OR_DIR_OR_FIGCAPTION_OR_FIGURE_OR_FOOTER_OR_HEADER_OR_HGROUP_OR_MAIN_OR_NAV_OR_SECTION_OR_SUMMARY | SPECIAL);
+public static final ElementName RP = new ElementName("rp", "rp", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.RT_OR_RP | OPTIONAL_END_TAG);
+public static final ElementName OPTGROUP = new ElementName("optgroup", "optgroup", 
+// CPPONLY: NS_NewHTMLOptGroupElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.OPTGROUP | OPTIONAL_END_TAG);
+public static final ElementName SAMP = new ElementName("samp", "samp", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.OTHER);
+public static final ElementName STOP = new ElementName("stop", "stop", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGStopElement, 
+TreeBuilder.OTHER);
+public static final ElementName BR = new ElementName("br", "br", 
+// CPPONLY: NS_NewHTMLBRElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.BR | SPECIAL);
+public static final ElementName ABBR = new ElementName("abbr", "abbr", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.OTHER);
+public static final ElementName ANIMATECOLOR = new ElementName("animatecolor", "animateColor", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.OTHER);
+public static final ElementName CENTER = new ElementName("center", "center", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.DIV_OR_BLOCKQUOTE_OR_CENTER_OR_MENU | SPECIAL);
+public static final ElementName HR = new ElementName("hr", "hr", 
+// CPPONLY: NS_NewHTMLHRElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.HR | SPECIAL);
+public static final ElementName FEFUNCR = new ElementName("fefuncr", "feFuncR", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGFEFuncRElement, 
+TreeBuilder.OTHER);
+public static final ElementName FECOMPONENTTRANSFER = new ElementName("fecomponenttransfer", "feComponentTransfer", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGFEComponentTransferElement, 
+TreeBuilder.OTHER);
+public static final ElementName FILTER = new ElementName("filter", "filter", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGFilterElement, 
+TreeBuilder.OTHER);
+public static final ElementName FOOTER = new ElementName("footer", "footer", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.ADDRESS_OR_ARTICLE_OR_ASIDE_OR_DETAILS_OR_DIALOG_OR_DIR_OR_FIGCAPTION_OR_FIGURE_OR_FOOTER_OR_HEADER_OR_HGROUP_OR_MAIN_OR_NAV_OR_SECTION_OR_SUMMARY | SPECIAL);
+public static final ElementName FEGAUSSIANBLUR = new ElementName("fegaussianblur", "feGaussianBlur", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGFEGaussianBlurElement, 
+TreeBuilder.OTHER);
+public static final ElementName HEADER = new ElementName("header", "header", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.ADDRESS_OR_ARTICLE_OR_ASIDE_OR_DETAILS_OR_DIALOG_OR_DIR_OR_FIGCAPTION_OR_FIGURE_OR_FOOTER_OR_HEADER_OR_HGROUP_OR_MAIN_OR_NAV_OR_SECTION_OR_SUMMARY | SPECIAL);
+public static final ElementName MARKER = new ElementName("marker", "marker", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGMarkerElement, 
+TreeBuilder.OTHER);
+public static final ElementName METER = new ElementName("meter", "meter", 
+// CPPONLY: NS_NewHTMLMeterElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.OTHER);
+public static final ElementName NOBR = new ElementName("nobr", "nobr", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.NOBR);
+public static final ElementName TR = new ElementName("tr", "tr", 
+// CPPONLY: NS_NewHTMLTableRowElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.TR | SPECIAL | FOSTER_PARENTING | OPTIONAL_END_TAG);
+public static final ElementName ADDRESS = new ElementName("address", "address", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.ADDRESS_OR_ARTICLE_OR_ASIDE_OR_DETAILS_OR_DIALOG_OR_DIR_OR_FIGCAPTION_OR_FIGURE_OR_FOOTER_OR_HEADER_OR_HGROUP_OR_MAIN_OR_NAV_OR_SECTION_OR_SUMMARY | SPECIAL);
+public static final ElementName CANVAS = new ElementName("canvas", "canvas", 
+// CPPONLY: NS_NewHTMLCanvasElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.OTHER);
+public static final ElementName DEFS = new ElementName("defs", "defs", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGDefsElement, 
+TreeBuilder.OTHER);
+public static final ElementName DETAILS = new ElementName("details", "details", 
+// CPPONLY: NS_NewHTMLDetailsElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.ADDRESS_OR_ARTICLE_OR_ASIDE_OR_DETAILS_OR_DIALOG_OR_DIR_OR_FIGCAPTION_OR_FIGURE_OR_FOOTER_OR_HEADER_OR_HGROUP_OR_MAIN_OR_NAV_OR_SECTION_OR_SUMMARY | SPECIAL);
+public static final ElementName MS = new ElementName("ms", "ms", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.MI_MO_MN_MS_MTEXT | SCOPING_AS_MATHML);
+public static final ElementName NOFRAMES = new ElementName("noframes", "noframes", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.NOFRAMES | SPECIAL);
+public static final ElementName PROGRESS = new ElementName("progress", "progress", 
+// CPPONLY: NS_NewHTMLProgressElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.OTHER);
+public static final ElementName DT = new ElementName("dt", "dt", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.DD_OR_DT | SPECIAL | OPTIONAL_END_TAG);
+public static final ElementName APPLET = new ElementName("applet", "applet", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.MARQUEE_OR_APPLET | SPECIAL | SCOPING);
+public static final ElementName BASEFONT = new ElementName("basefont", "basefont", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.LINK_OR_BASEFONT_OR_BGSOUND | SPECIAL);
+public static final ElementName CONTENT = new ElementName("content", "content", 
+// CPPONLY: NS_NewHTMLContentElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.OTHER);
+public static final ElementName DATALIST = new ElementName("datalist", "datalist", 
+// CPPONLY: NS_NewHTMLDataListElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.OTHER);
+public static final ElementName FOREIGNOBJECT = new ElementName("foreignobject", "foreignObject", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGForeignObjectElement, 
+TreeBuilder.FOREIGNOBJECT_OR_DESC | SCOPING_AS_SVG);
+public static final ElementName FIELDSET = new ElementName("fieldset", "fieldset", 
+// CPPONLY: NS_NewHTMLFieldSetElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.FIELDSET | SPECIAL);
+public static final ElementName FRAMESET = new ElementName("frameset", "frameset", 
+// CPPONLY: NS_NewHTMLFrameSetElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.FRAMESET | SPECIAL);
+public static final ElementName FEOFFSET = new ElementName("feoffset", "feOffset", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGFEOffsetElement, 
+TreeBuilder.OTHER);
+public static final ElementName FESPOTLIGHT = new ElementName("fespotlight", "feSpotLight", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGFESpotLightElement, 
+TreeBuilder.OTHER);
+public static final ElementName FEPOINTLIGHT = new ElementName("fepointlight", "fePointLight", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGFEPointLightElement, 
+TreeBuilder.OTHER);
+public static final ElementName FEDISTANTLIGHT = new ElementName("fedistantlight", "feDistantLight", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGFEDistantLightElement, 
+TreeBuilder.OTHER);
+public static final ElementName FONT = new ElementName("font", "font", 
+// CPPONLY: NS_NewHTMLFontElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.FONT);
+public static final ElementName INPUT = new ElementName("input", "input", 
+// CPPONLY: NS_NewHTMLInputElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.INPUT | SPECIAL);
+public static final ElementName LINEARGRADIENT = new ElementName("lineargradient", "linearGradient", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGLinearGradientElement, 
+TreeBuilder.OTHER);
+public static final ElementName MTEXT = new ElementName("mtext", "mtext", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.MI_MO_MN_MS_MTEXT | SCOPING_AS_MATHML);
+public static final ElementName NOSCRIPT = new ElementName("noscript", "noscript", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.NOSCRIPT | SPECIAL);
+public static final ElementName RT = new ElementName("rt", "rt", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.RT_OR_RP | OPTIONAL_END_TAG);
+public static final ElementName OBJECT = new ElementName("object", "object", 
+// CPPONLY: NS_NewHTMLObjectElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.OBJECT | SPECIAL | SCOPING);
+public static final ElementName OUTPUT = new ElementName("output", "output", 
+// CPPONLY: NS_NewHTMLOutputElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.OUTPUT);
+public static final ElementName PLAINTEXT = new ElementName("plaintext", "plaintext", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.PLAINTEXT | SPECIAL);
+public static final ElementName TT = new ElementName("tt", "tt", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.B_OR_BIG_OR_CODE_OR_EM_OR_I_OR_S_OR_SMALL_OR_STRIKE_OR_STRONG_OR_TT_OR_U);
+public static final ElementName RECT = new ElementName("rect", "rect", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGRectElement, 
+TreeBuilder.OTHER);
+public static final ElementName RADIALGRADIENT = new ElementName("radialgradient", "radialGradient", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGRadialGradientElement, 
+TreeBuilder.OTHER);
+public static final ElementName SELECT = new ElementName("select", "select", 
+// CPPONLY: NS_NewHTMLSelectElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.SELECT | SPECIAL);
+public static final ElementName SCRIPT = new ElementName("script", "script", 
+// CPPONLY: NS_NewHTMLScriptElement,
+// CPPONLY: NS_NewSVGScriptElement, 
+TreeBuilder.SCRIPT | SPECIAL);
+public static final ElementName TFOOT = new ElementName("tfoot", "tfoot", 
+// CPPONLY: NS_NewHTMLTableSectionElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.TBODY_OR_THEAD_OR_TFOOT | SPECIAL | FOSTER_PARENTING | OPTIONAL_END_TAG);
+public static final ElementName TEXT = new ElementName("text", "text", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGTextElement, 
+TreeBuilder.OTHER);
+public static final ElementName MENU = new ElementName("menu", "menu", 
+// CPPONLY: NS_NewHTMLMenuElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.DIV_OR_BLOCKQUOTE_OR_CENTER_OR_MENU | SPECIAL);
+public static final ElementName FEDROPSHADOW = new ElementName("fedropshadow", "feDropShadow", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGFEDropShadowElement, 
+TreeBuilder.OTHER);
+public static final ElementName VIEW = new ElementName("view", "view", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGViewElement, 
+TreeBuilder.OTHER);
+public static final ElementName FECOLORMATRIX = new ElementName("fecolormatrix", "feColorMatrix", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGFEColorMatrixElement, 
+TreeBuilder.OTHER);
+public static final ElementName FECONVOLVEMATRIX = new ElementName("feconvolvematrix", "feConvolveMatrix", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGFEConvolveMatrixElement, 
+TreeBuilder.OTHER);
+public static final ElementName BODY = new ElementName("body", "body", 
+// CPPONLY: NS_NewHTMLBodyElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.BODY | SPECIAL | OPTIONAL_END_TAG);
+public static final ElementName FEMORPHOLOGY = new ElementName("femorphology", "feMorphology", 
+// CPPONLY: NS_NewHTMLUnknownElement,
+// CPPONLY: NS_NewSVGFEMorphologyElement, 
+TreeBuilder.OTHER);
+public static final ElementName RUBY = new ElementName("ruby", "ruby", 
+// CPPONLY: NS_NewHTMLElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.RUBY_OR_SPAN_OR_SUB_OR_SUP_OR_VAR);
+public static final ElementName SUMMARY = new ElementName("summary", "summary", 
+// CPPONLY: NS_NewHTMLSummaryElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.ADDRESS_OR_ARTICLE_OR_ASIDE_OR_DETAILS_OR_DIALOG_OR_DIR_OR_FIGCAPTION_OR_FIGURE_OR_FOOTER_OR_HEADER_OR_HGROUP_OR_MAIN_OR_NAV_OR_SECTION_OR_SUMMARY | SPECIAL);
+public static final ElementName TBODY = new ElementName("tbody", "tbody", 
+// CPPONLY: NS_NewHTMLTableSectionElement,
+// CPPONLY: NS_NewSVGUnknownElement, 
+TreeBuilder.TBODY_OR_THEAD_OR_TFOOT | SPECIAL | FOSTER_PARENTING | OPTIONAL_END_TAG);
+private final static @NoLength ElementName[] ELEMENT_NAMES = {
+MN,
+ELLIPSE,
+FIELDSET,
+H2,
+MGLYPH,
+METER,
+RECT,
+RTC,
+EMBED,
+STRIKE,
+OL,
+OPTGROUP,
+NOFRAMES,
+LINEARGRADIENT,
+VIEW,
+IMG,
+WBR,
+METADATA,
+ASIDE,
+FECOMPOSITE,
+DIALOG,
+MI,
+EM,
+TSPAN,
+FEFUNCR,
+CANVAS,
+BASEFONT,
+FEPOINTLIGHT,
+OBJECT,
+TFOOT,
+FEMORPHOLOGY,
+DEL,
+NAV,
+SET,
+Q,
+H6,
+RB,
+LEGEND,
+BLOCKQUOTE,
+FEMERGE,
+MARQUEE,
+TIME,
+LISTING,
+TH,
+MASK,
+SYMBOL,
+ANIMATEMOTION,
+POLYGON,
+COLGROUP,
+ABBR,
+FEGAUSSIANBLUR,
+TR,
+DETAILS,
+DT,
+DATALIST,
+FEOFFSET,
+FONT,
+NOSCRIPT,
+PLAINTEXT,
+SELECT,
+MENU,
+FECONVOLVEMATRIX,
+SUMMARY,
+BDO,
+DIR,
+KBD,
+A,
+SVG,
+VAR,
+I,
+U,
+H4,
+DATA,
+TEXTAREA,
+DD,
+FEFLOOD,
+TD,
+ANIMATE,
+CIRCLE,
+FEMERGENODE,
+FRAME,
+IFRAME,
+PICTURE,
+TABLE,
+ALTGLYPHDEF,
+FEDIFFUSELIGHTING,
+ALTGLYPH,
+MPATH,
+TEXTPATH,
+MARK,
+DL,
+UL,
+ANIMATETRANSFORM,
+MENUITEM,
+CAPTION,
+MAIN,
+SPAN,
+MO,
+HGROUP,
+STOP,
+CENTER,
+FILTER,
+MARKER,
+NOBR,
+ADDRESS,
+DEFS,
+MS,
+PROGRESS,
+APPLET,
+CONTENT,
+FOREIGNOBJECT,
+FRAMESET,
+FESPOTLIGHT,
+FEDISTANTLIGHT,
+INPUT,
+MTEXT,
+RT,
+OUTPUT,
+TT,
+RADIALGRADIENT,
+SCRIPT,
+TEXT,
+FEDROPSHADOW,
+FECOLORMATRIX,
+BODY,
+RUBY,
+TBODY,
+BIG,
+COL,
+DFN,
+DIV,
+INS,
+MAP,
+PRE,
+B,
+SUB,
+SUP,
+USE,
+G,
+XMP,
+P,
+S,
+H1,
+H3,
+H5,
+AREA,
+FEFUNCA,
+META,
+FEFUNCB,
+DESC,
+BGSOUND,
+FEBLEND,
+HEAD,
+NOEMBED,
+THEAD,
+ARTICLE,
+BASE,
+CODE,
+CITE,
+FETURBULENCE,
+FEIMAGE,
+FETILE,
+FIGURE,
+IMAGE,
+LINE,
+POLYLINE,
+SOURCE,
+STYLE,
+TITLE,
+TEMPLATE,
+GLYPHREF,
+FEFUNCG,
+FESPECULARLIGHTING,
+STRONG,
+CLIPPATH,
+MATH,
+PATH,
+SWITCH,
+LI,
+LINK,
+MALIGNMARK,
+TRACK,
+HTML,
+LABEL,
+SMALL,
+ALTGLYPHITEM,
+ACRONYM,
+FORM,
+PARAM,
+BUTTON,
+FIGCAPTION,
+KEYGEN,
+OPTION,
+PATTERN,
+SECTION,
+AUDIO,
+VIDEO,
+FEDISPLACEMENTMAP,
+RP,
+SAMP,
+BR,
+ANIMATECOLOR,
+HR,
+FECOMPONENTTRANSFER,
+FOOTER,
+HEADER,
+};
+private final static int[] ELEMENT_HASHES = {
+1902641154,
+1749395095,
+2001349704,
+893386754,
+1803876550,
+1971465813,
+2007601444,
+59821379,
+1732381397,
+1756600614,
+1870135298,
+1939219752,
+1988763672,
+2004635806,
+2060065124,
+55104723,
+62450211,
+1686489160,
+1747048757,
+1749932347,
+1782357526,
+1818755074,
+1881669634,
+1907959605,
+1967760215,
+1982935782,
+1999397992,
+2001392796,
+2006028454,
+2008851557,
+2085266636,
+52485715,
+57733651,
+60354131,
+67633153,
+960495618,
+1703936002,
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