--- a/dom/base/Element.cpp
+++ b/dom/base/Element.cpp
@@ -3072,20 +3072,16 @@ nsDOMTokenListPropertyDestructor(void *a
 {
   nsDOMTokenList* list =
     static_cast<nsDOMTokenList*>(aPropertyValue);
   NS_RELEASE(list);
 }
 
 static nsIAtom** sPropertiesToTraverseAndUnlink[] =
   {
-    &nsGkAtoms::microdataProperties,
-    &nsGkAtoms::itemtype,
-    &nsGkAtoms::itemref,
-    &nsGkAtoms::itemprop,
     &nsGkAtoms::sandbox,
     &nsGkAtoms::sizes,
     nullptr
   };
 
 // static
 nsIAtom***
 Element::HTMLSVGPropertiesToTraverseAndUnlink()
@@ -3117,36 +3113,16 @@ Element::GetTokenList(nsIAtom* aAtom,
   if (!list) {
     list = new nsDOMTokenList(this, aAtom, aSupportedTokens);
     NS_ADDREF(list);
     SetProperty(aAtom, list, nsDOMTokenListPropertyDestructor);
   }
   return list;
 }
 
-void
-Element::GetTokenList(nsIAtom* aAtom, nsIVariant** aResult)
-{
-  nsISupports* itemType = GetTokenList(aAtom);
-  nsCOMPtr<nsIWritableVariant> out = new nsVariant();
-  out->SetAsInterface(NS_GET_IID(nsISupports), itemType);
-  out.forget(aResult);
-}
-
-nsresult
-Element::SetTokenList(nsIAtom* aAtom, nsIVariant* aValue)
-{
-  nsDOMTokenList* itemType = GetTokenList(aAtom);
-  nsAutoString string;
-  aValue->GetAsAString(string);
-  ErrorResult rv;
-  itemType->SetValue(string, rv);
-  return rv.StealNSResult();
-}
-
 Element*
 Element::Closest(const nsAString& aSelector, ErrorResult& aResult)
 {
   nsCSSSelectorList* selectorList = ParseSelectorList(aSelector, aResult);
   if (!selectorList) {
     // Either we failed (and aResult already has the exception), or this
     // is a pseudo-element-only selector that matches nothing.
     return nullptr;

--- a/dom/base/Element.h
+++ b/dom/base/Element.h
@@ -1331,18 +1331,16 @@ protected:
    * this gets the value of the xlink:_moz_target attribute, or failing that,
    * the value of xlink:show, converted to a suitably equivalent named target
    * (e.g. _blank).
    */
   virtual void GetLinkTarget(nsAString& aTarget);
 
   nsDOMTokenList* GetTokenList(nsIAtom* aAtom,
                                const DOMTokenListSupportedTokenArray aSupportedTokens = nullptr);
-  void GetTokenList(nsIAtom* aAtom, nsIVariant** aResult);
-  nsresult SetTokenList(nsIAtom* aAtom, nsIVariant* aValue);
 
 private:
   /**
    * Get this element's client area rect in app units.
    * @return the frame's client area
    */
   nsRect GetClientAreaRect();
 

--- a/dom/base/nsGkAtomList.h
+++ b/dom/base/nsGkAtomList.h
@@ -597,17 +597,16 @@ GK_ATOM(menulist, "menulist")
 GK_ATOM(menupopup, "menupopup")
 GK_ATOM(menuseparator, "menuseparator")
 GK_ATOM(message, "message")
 GK_ATOM(meta, "meta")
 GK_ATOM(referrer, "referrer")
 GK_ATOM(referrerpolicy, "referrerpolicy")
 GK_ATOM(meter, "meter")
 GK_ATOM(method, "method")
-GK_ATOM(microdataProperties, "microdataProperties")
 GK_ATOM(middle, "middle")
 GK_ATOM(min, "min")
 GK_ATOM(minheight, "minheight")
 GK_ATOM(minimum_scale, "minimum-scale")
 GK_ATOM(minpos, "minpos")
 GK_ATOM(minusSign, "minus-sign")
 GK_ATOM(minwidth, "minwidth")
 GK_ATOM(_mixed, "mixed")

--- a/dom/bindings/Bindings.conf
+++ b/dom/bindings/Bindings.conf
@@ -569,20 +569,16 @@ DOMInterfaces = {
 'HTMLOListElement': {
     'nativeType' : 'mozilla::dom::HTMLSharedListElement'
 },
 
 'HTMLParamElement': {
     'nativeType': 'mozilla::dom::HTMLSharedElement'
 },
 
-'HTMLPropertiesCollection': {
-    'headerFile': 'HTMLPropertiesCollection.h',
-},
-
 'HTMLQuoteElement': {
     'nativeType': 'mozilla::dom::HTMLSharedElement'
 },
 
 'HTMLTextAreaElement': {
     'binaryNames': {
         'textLength': 'getTextLength'
     }
@@ -924,20 +920,16 @@ DOMInterfaces = {
 'PromiseDebugging': {
     'concrete': False,
 },
 
 'PromiseNativeHandler': {
     'wrapperCache': False,
 },
 
-'PropertyNodeList': {
-    'headerFile': 'HTMLPropertiesCollection.h',
-},
-
 'PushEvent': {
     'headerFile': 'ServiceWorkerEvents.h',
     'nativeType': 'mozilla::dom::workers::PushEvent',
 },
 
 'PushMessageData': {
     'headerFile': 'ServiceWorkerEvents.h',
     'nativeType': 'mozilla::dom::workers::PushMessageData',

--- a/dom/html/HTMLAnchorElement.cpp
+++ b/dom/html/HTMLAnchorElement.cpp
@@ -97,28 +97,16 @@ NS_IMPL_STRING_ATTR(HTMLAnchorElement, T
 NS_IMPL_STRING_ATTR(HTMLAnchorElement, Download, download)
 
 int32_t
 HTMLAnchorElement::TabIndexDefault()
 {
   return 0;
 }
 
-void
-HTMLAnchorElement::GetItemValueText(DOMString& aValue)
-{
-  GetHref(aValue);
-}
-
-void
-HTMLAnchorElement::SetItemValueText(const nsAString& aValue)
-{
-  SetHref(aValue);
-}
-
 bool
 HTMLAnchorElement::Draggable() const
 {
   // links can be dragged as long as there is an href and the
   // draggable attribute isn't false
   if (!HasAttr(kNameSpaceID_None, nsGkAtoms::href)) {
     // no href, so just use the same behavior as other elements
     return nsGenericHTMLElement::Draggable();

--- a/dom/html/HTMLAnchorElement.h
+++ b/dom/html/HTMLAnchorElement.h
@@ -227,18 +227,16 @@ public:
     GetHref(aResult);
   }
 
   static DOMTokenListSupportedToken sSupportedRelValues[];
 
 protected:
   virtual ~HTMLAnchorElement();
 
-  virtual void GetItemValueText(DOMString& text) override;
-  virtual void SetItemValueText(const nsAString& text) override;
   virtual JSObject* WrapNode(JSContext *aCx, JS::Handle<JSObject*> aGivenProto) override;
   RefPtr<nsDOMTokenList > mRelList;
 };
 
 } // namespace dom
 } // namespace mozilla
 
 #endif // mozilla_dom_HTMLAnchorElement_h

--- a/dom/html/HTMLAreaElement.cpp
+++ b/dom/html/HTMLAreaElement.cpp
@@ -60,28 +60,16 @@ NS_IMPL_STRING_ATTR(HTMLAreaElement, Sha
 NS_IMPL_STRING_ATTR(HTMLAreaElement, Download, download)
 
 int32_t
 HTMLAreaElement::TabIndexDefault()
 {
   return 0;
 }
 
-void
-HTMLAreaElement::GetItemValueText(DOMString& aValue)
-{
-  GetHref(aValue);
-}
-
-void
-HTMLAreaElement::SetItemValueText(const nsAString& aValue)
-{
-  SetHref(aValue);
-}
-
 NS_IMETHODIMP
 HTMLAreaElement::GetTarget(nsAString& aValue)
 {
   if (!GetAttr(kNameSpaceID_None, nsGkAtoms::target, aValue)) {
     GetBaseTarget(aValue);
   }
   return NS_OK;
 }

--- a/dom/html/HTMLAreaElement.h
+++ b/dom/html/HTMLAreaElement.h
@@ -180,17 +180,15 @@ public:
     GetHref(aResult);
   }
 
 protected:
   virtual ~HTMLAreaElement();
 
   virtual JSObject* WrapNode(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;
 
-  virtual void GetItemValueText(DOMString& text) override;
-  virtual void SetItemValueText(const nsAString& text) override;
   RefPtr<nsDOMTokenList > mRelList;
 };
 
 } // namespace dom
 } // namespace mozilla
 
 #endif /* mozilla_dom_HTMLAreaElement_h */

--- a/dom/html/HTMLDataElement.cpp
+++ b/dom/html/HTMLDataElement.cpp
@@ -25,23 +25,10 @@ HTMLDataElement::~HTMLDataElement()
 NS_IMPL_ELEMENT_CLONE(HTMLDataElement)
 
 JSObject*
 HTMLDataElement::WrapNode(JSContext* aCx, JS::Handle<JSObject*> aGivenProto)
 {
   return HTMLDataElementBinding::Wrap(aCx, this, aGivenProto);
 }
 
-void
-HTMLDataElement::GetItemValueText(DOMString& text)
-{
-  GetValue(text);
-}
-
-void
-HTMLDataElement::SetItemValueText(const nsAString& text)
-{
-  ErrorResult rv;
-  SetValue(text, rv);
-}
-
 } // namespace dom
 } // namespace mozilla

--- a/dom/html/HTMLDataElement.h
+++ b/dom/html/HTMLDataElement.h
@@ -26,18 +26,16 @@ public:
     GetHTMLAttr(nsGkAtoms::value, aValue);
   }
 
   void SetValue(const nsAString& aValue, ErrorResult& aError)
   {
     SetHTMLAttr(nsGkAtoms::value, aValue, aError);
   }
 
-  virtual void GetItemValueText(DOMString& text) override;
-  virtual void SetItemValueText(const nsAString& text) override;
   virtual nsresult Clone(mozilla::dom::NodeInfo* aNodeInfo, nsINode** aResult) const override;
 
 protected:
   virtual ~HTMLDataElement();
 
   virtual JSObject* WrapNode(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;
 };
 

--- a/dom/html/HTMLIFrameElement.cpp
+++ b/dom/html/HTMLIFrameElement.cpp
@@ -50,28 +50,16 @@ NS_IMPL_STRING_ATTR(HTMLIFrameElement, M
 NS_IMPL_STRING_ATTR(HTMLIFrameElement, MarginWidth, marginwidth)
 NS_IMPL_STRING_ATTR(HTMLIFrameElement, Name, name)
 NS_IMPL_STRING_ATTR(HTMLIFrameElement, Scrolling, scrolling)
 NS_IMPL_URI_ATTR(HTMLIFrameElement, Src, src)
 NS_IMPL_STRING_ATTR(HTMLIFrameElement, Width, width)
 NS_IMPL_BOOL_ATTR(HTMLIFrameElement, AllowFullscreen, allowfullscreen)
 NS_IMPL_STRING_ATTR(HTMLIFrameElement, Srcdoc, srcdoc)
 
-void
-HTMLIFrameElement::GetItemValueText(DOMString& aValue)
-{
-  GetSrc(aValue);
-}
-
-void
-HTMLIFrameElement::SetItemValueText(const nsAString& aValue)
-{
-  SetSrc(aValue);
-}
-
 NS_IMETHODIMP
 HTMLIFrameElement::GetContentDocument(nsIDOMDocument** aContentDocument)
 {
   return nsGenericHTMLFrameElement::GetContentDocument(aContentDocument);
 }
 
 bool
 HTMLIFrameElement::ParseAttribute(int32_t aNamespaceID,

--- a/dom/html/HTMLIFrameElement.h
+++ b/dom/html/HTMLIFrameElement.h
@@ -188,19 +188,16 @@ public:
   // set, the fullscreen state of this element will not be reverted
   // automatically when its subdocument exits fullscreen.
   bool FullscreenFlag() const { return mFullscreenFlag; }
   void SetFullscreenFlag(bool aValue) { mFullscreenFlag = aValue; }
 
 protected:
   virtual ~HTMLIFrameElement();
 
-  virtual void GetItemValueText(DOMString& text) override;
-  virtual void SetItemValueText(const nsAString& text) override;
-
   virtual JSObject* WrapNode(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;
 
 private:
   static void MapAttributesIntoRule(const nsMappedAttributes* aAttributes,
                                     nsRuleData* aData);
 
   static const DOMTokenListSupportedToken sSupportedSandboxTokens[];
 };

--- a/dom/html/HTMLImageElement.cpp
+++ b/dom/html/HTMLImageElement.cpp
@@ -190,28 +190,16 @@ HTMLImageElement::GetCurrentSrc(nsAStrin
     CopyUTF8toUTF16(spec, aValue);
   } else {
     SetDOMStringToNull(aValue);
   }
 
   return NS_OK;
 }
 
-void
-HTMLImageElement::GetItemValueText(DOMString& aValue)
-{
-  GetSrc(aValue);
-}
-
-void
-HTMLImageElement::SetItemValueText(const nsAString& aValue)
-{
-  SetSrc(aValue);
-}
-
 bool
 HTMLImageElement::Draggable() const
 {
   // images may be dragged unless the draggable attribute is false
   return !AttrValueIs(kNameSpaceID_None, nsGkAtoms::draggable,
                       nsGkAtoms::_false, eIgnoreCase);
 }
 

--- a/dom/html/HTMLImageElement.h
+++ b/dom/html/HTMLImageElement.h
@@ -333,18 +333,16 @@ protected:
   // If the node's srcset/sizes make for an invalid selector, returns
   // false. This does not guarantee the resulting selector matches an image,
   // only that it is valid.
   bool TryCreateResponsiveSelector(nsIContent *aSourceNode,
                                    const nsAString *aSrcset = nullptr,
                                    const nsAString *aSizes = nullptr);
 
   CSSIntPoint GetXY();
-  virtual void GetItemValueText(DOMString& text) override;
-  virtual void SetItemValueText(const nsAString& text) override;
   virtual JSObject* WrapNode(JSContext *aCx, JS::Handle<JSObject*> aGivenProto) override;
   void UpdateFormOwner();
 
   virtual nsresult BeforeSetAttr(int32_t aNameSpaceID, nsIAtom* aName,
                                  nsAttrValueOrString* aValue,
                                  bool aNotify) override;
 
   virtual nsresult AfterSetAttr(int32_t aNameSpaceID, nsIAtom* aName,

--- a/dom/html/HTMLLinkElement.cpp
+++ b/dom/html/HTMLLinkElement.cpp
@@ -127,28 +127,16 @@ NS_IMPL_URI_ATTR(HTMLLinkElement, Href, 
 NS_IMPL_STRING_ATTR(HTMLLinkElement, Hreflang, hreflang)
 NS_IMPL_STRING_ATTR(HTMLLinkElement, Media, media)
 NS_IMPL_STRING_ATTR(HTMLLinkElement, Rel, rel)
 NS_IMPL_STRING_ATTR(HTMLLinkElement, Rev, rev)
 NS_IMPL_STRING_ATTR(HTMLLinkElement, Target, target)
 NS_IMPL_STRING_ATTR(HTMLLinkElement, Type, type)
 
 void
-HTMLLinkElement::GetItemValueText(DOMString& aValue)
-{
-  GetHref(aValue);
-}
-
-void
-HTMLLinkElement::SetItemValueText(const nsAString& aValue)
-{
-  SetHref(aValue);
-}
-
-void
 HTMLLinkElement::OnDNSPrefetchRequested()
 {
   UnsetFlags(HTML_LINK_DNS_PREFETCH_DEFERRED);
   SetFlags(HTML_LINK_DNS_PREFETCH_REQUESTED);
 }
 
 void
 HTMLLinkElement::OnDNSPrefetchDeferred()

--- a/dom/html/HTMLLinkElement.h
+++ b/dom/html/HTMLLinkElement.h
@@ -164,21 +164,18 @@ protected:
   // nsStyleLinkElement
   virtual already_AddRefed<nsIURI> GetStyleSheetURL(bool* aIsInline) override;
   virtual void GetStyleSheetInfo(nsAString& aTitle,
                                  nsAString& aType,
                                  nsAString& aMedia,
                                  bool* aIsScoped,
                                  bool* aIsAlternate) override;
 protected:
-  // nsGenericHTMLElement
-  virtual void GetItemValueText(DOMString& text) override;
-  virtual void SetItemValueText(const nsAString& text) override;
+  RefPtr<nsDOMTokenList> mRelList;
 
-  RefPtr<nsDOMTokenList > mRelList;
 private:
   RefPtr<ImportLoader> mImportLoader;
 };
 
 } // namespace dom
 } // namespace mozilla
 
 #endif // mozilla_dom_HTMLLinkElement_h

--- a/dom/html/HTMLMediaElement.cpp
+++ b/dom/html/HTMLMediaElement.cpp
@@ -2320,30 +2320,16 @@ HTMLMediaElement::~HTMLMediaElement()
 
   if (mChannel) {
     mChannel->Cancel(NS_BINDING_ABORTED);
   }
 
   WakeLockRelease();
 }
 
-void
-HTMLMediaElement::GetItemValueText(DOMString& aValue)
-{
-  // Can't call GetSrc because we don't have a JSContext
-  GetURIAttr(nsGkAtoms::src, nullptr, aValue);
-}
-
-void
-HTMLMediaElement::SetItemValueText(const nsAString& aValue)
-{
-  // Can't call SetSrc because we don't have a JSContext
-  SetAttr(kNameSpaceID_None, nsGkAtoms::src, aValue, true);
-}
-
 void HTMLMediaElement::StopSuspendingAfterFirstFrame()
 {
   mAllowSuspendAfterFirstFrame = false;
   if (!mSuspendedAfterFirstFrame)
     return;
   mSuspendedAfterFirstFrame = false;
   if (mDecoder) {
     mDecoder->Resume();

--- a/dom/html/HTMLMediaElement.h
+++ b/dom/html/HTMLMediaElement.h
@@ -738,19 +738,16 @@ protected:
   class StreamSizeListener;
 
   MediaDecoderOwner::NextFrameStatus NextFrameStatus();
   void SetDecoder(MediaDecoder* aDecoder) {
     MOZ_ASSERT(aDecoder); // Use ShutdownDecoder() to clear.
     mDecoder = aDecoder;
   }
 
-  virtual void GetItemValueText(DOMString& text) override;
-  virtual void SetItemValueText(const nsAString& text) override;
-
   class WakeLockBoolWrapper {
   public:
     explicit WakeLockBoolWrapper(bool val = false)
       : mValue(val), mCanPlay(true), mOuter(nullptr) {}
 
     ~WakeLockBoolWrapper();
 
     void SetOuter(HTMLMediaElement* outer) { mOuter = outer; }

--- a/dom/html/HTMLMetaElement.cpp
+++ b/dom/html/HTMLMetaElement.cpp
@@ -33,28 +33,16 @@ NS_IMPL_ISUPPORTS_INHERITED(HTMLMetaElem
 NS_IMPL_ELEMENT_CLONE(HTMLMetaElement)
 
 
 NS_IMPL_STRING_ATTR(HTMLMetaElement, Content, content)
 NS_IMPL_STRING_ATTR(HTMLMetaElement, HttpEquiv, httpEquiv)
 NS_IMPL_STRING_ATTR(HTMLMetaElement, Name, name)
 NS_IMPL_STRING_ATTR(HTMLMetaElement, Scheme, scheme)
 
-void
-HTMLMetaElement::GetItemValueText(DOMString& aValue)
-{
-  GetContent(aValue);
-}
-
-void
-HTMLMetaElement::SetItemValueText(const nsAString& aValue)
-{
-  SetContent(aValue);
-}
-
 nsresult
 HTMLMetaElement::SetMetaReferrer(nsIDocument* aDocument)
 {
   if (!aDocument ||
       !AttrValueIs(kNameSpaceID_None, nsGkAtoms::name, nsGkAtoms::referrer, eIgnoreCase)) {
     return NS_OK;
   }
   nsAutoString content;

--- a/dom/html/HTMLMetaElement.h
+++ b/dom/html/HTMLMetaElement.h
@@ -60,19 +60,16 @@ public:
     SetHTMLAttr(nsGkAtoms::scheme, aScheme, aRv);
   }
 
   virtual JSObject* WrapNode(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;
 
 protected:
   virtual ~HTMLMetaElement();
 
-  virtual void GetItemValueText(DOMString& text) override;
-  virtual void SetItemValueText(const nsAString& text) override;
-
 private:
   nsresult SetMetaReferrer(nsIDocument* aDocument);
 };
 
 } // namespace dom
 } // namespace mozilla
 
 #endif // mozilla_dom_HTMLMetaElement_h

--- a/dom/html/HTMLObjectElement.cpp
+++ b/dom/html/HTMLObjectElement.cpp
@@ -239,28 +239,16 @@ HTMLObjectElement::PostHandleEvent(Event
 #endif // #ifdef XP_MACOSX
 
 NS_IMETHODIMP
 HTMLObjectElement::GetForm(nsIDOMHTMLFormElement **aForm)
 {
   return nsGenericHTMLFormElement::GetForm(aForm);
 }
 
-void
-HTMLObjectElement::GetItemValueText(DOMString& aValue)
-{
-  GetData(aValue);
-}
-
-void
-HTMLObjectElement::SetItemValueText(const nsAString& aValue)
-{
-  SetData(aValue);
-}
-
 nsresult
 HTMLObjectElement::BindToTree(nsIDocument *aDocument,
                               nsIContent *aParent,
                               nsIContent *aBindingParent,
                               bool aCompileEventHandlers)
 {
   nsresult rv = nsGenericHTMLFormElement::BindToTree(aDocument, aParent,
                                                      aBindingParent,

--- a/dom/html/HTMLObjectElement.h
+++ b/dom/html/HTMLObjectElement.h
@@ -249,19 +249,16 @@ private:
    */
   bool IsFocusableForTabIndex();
 
   nsContentPolicyType GetContentPolicyType() const override
   {
     return nsIContentPolicy::TYPE_INTERNAL_OBJECT;
   }
 
-  virtual void GetItemValueText(DOMString& text) override;
-  virtual void SetItemValueText(const nsAString& text) override;
-
   virtual ~HTMLObjectElement();
 
   virtual JSObject* WrapNode(JSContext *aCx, JS::Handle<JSObject*> aGivenProto) override;
 
   static void MapAttributesIntoRule(const nsMappedAttributes* aAttributes,
                                     nsRuleData* aData);
 
   bool mIsDoneAddingChildren;

deleted file mode 100644
--- a/dom/html/HTMLPropertiesCollection.cpp
+++ /dev/null
@@ -1,518 +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 "HTMLPropertiesCollection.h"
-#include "nsIDocument.h"
-#include "nsContentUtils.h"
-#include "nsGenericHTMLElement.h"
-#include "nsVariant.h"
-#include "nsDOMTokenList.h"
-#include "nsAttrValue.h"
-#include "nsWrapperCacheInlines.h"
-#include "mozilla/dom/HTMLPropertiesCollectionBinding.h"
-#include "jsapi.h"
-#include "MainThreadUtils.h"
-#include "mozilla/Assertions.h"
-
-namespace mozilla {
-namespace dom {
-
-NS_IMPL_CYCLE_COLLECTION_CLASS(HTMLPropertiesCollection)
-
-NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(HTMLPropertiesCollection)
-  // SetDocument(nullptr) ensures that we remove ourselves as a mutation observer
-  tmp->SetDocument(nullptr);
-  NS_IMPL_CYCLE_COLLECTION_UNLINK(mRoot)
-  NS_IMPL_CYCLE_COLLECTION_UNLINK(mNames)
-  NS_IMPL_CYCLE_COLLECTION_UNLINK(mNamedItemEntries)
-  NS_IMPL_CYCLE_COLLECTION_UNLINK(mProperties)
-  NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER
-NS_IMPL_CYCLE_COLLECTION_UNLINK_END
-NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(HTMLPropertiesCollection)
-  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mDoc)
-  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mRoot)
-  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mNames)
-  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mNamedItemEntries);
-  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mProperties)
-  NS_IMPL_CYCLE_COLLECTION_TRAVERSE_SCRIPT_OBJECTS
-NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
-NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(HTMLPropertiesCollection)
-  NS_IMPL_CYCLE_COLLECTION_TRACE_PRESERVED_WRAPPER
-NS_IMPL_CYCLE_COLLECTION_TRACE_END
-
-HTMLPropertiesCollection::HTMLPropertiesCollection(nsGenericHTMLElement* aRoot)
-  : mRoot(aRoot)
-  , mDoc(aRoot->GetUncomposedDoc())
-  , mIsDirty(true)
-{
-  mNames = new PropertyStringList(this);
-  if (mDoc) {
-    mDoc->AddMutationObserver(this);
-  }
-}
-
-HTMLPropertiesCollection::~HTMLPropertiesCollection()
-{
-  if (mDoc) {
-    mDoc->RemoveMutationObserver(this);
-  }
-}
-
-NS_INTERFACE_TABLE_HEAD(HTMLPropertiesCollection)
-    NS_WRAPPERCACHE_INTERFACE_TABLE_ENTRY
-    NS_INTERFACE_TABLE(HTMLPropertiesCollection,
-                       nsIDOMHTMLCollection,
-                       nsIHTMLCollection,
-                       nsIMutationObserver)
-    NS_INTERFACE_TABLE_TO_MAP_SEGUE_CYCLE_COLLECTION(HTMLPropertiesCollection)
-NS_INTERFACE_MAP_END
-
-NS_IMPL_CYCLE_COLLECTING_ADDREF(HTMLPropertiesCollection)
-NS_IMPL_CYCLE_COLLECTING_RELEASE(HTMLPropertiesCollection)
-
-void
-HTMLPropertiesCollection::SetDocument(nsIDocument* aDocument) {
-  if (mDoc) {
-    mDoc->RemoveMutationObserver(this);
-  }
-  mDoc = aDocument;
-  if (mDoc) {
-    mDoc->AddMutationObserver(this);
-  }
-  for (auto iter = mNamedItemEntries.Iter(); !iter.Done(); iter.Next()) {
-    iter.UserData()->SetDocument(aDocument);
-  }
-  mIsDirty = true;
-}
-
-JSObject*
-HTMLPropertiesCollection::WrapObject(JSContext* cx, JS::Handle<JSObject*> aGivenProto)
-{
-  return HTMLPropertiesCollectionBinding::Wrap(cx, this, aGivenProto);
-}
-
-NS_IMETHODIMP
-HTMLPropertiesCollection::GetLength(uint32_t* aLength)
-{
-  EnsureFresh();
-  *aLength = mProperties.Length();
-  return NS_OK;
-}
-
-NS_IMETHODIMP
-HTMLPropertiesCollection::Item(uint32_t aIndex, nsIDOMNode** aResult)
-{
-  nsINode* result = nsIHTMLCollection::Item(aIndex);
-  if (result) {
-    NS_ADDREF(*aResult = result->AsDOMNode());
-  } else {
-    *aResult = nullptr;
-  }
-  return NS_OK;
-}
-
-NS_IMETHODIMP
-HTMLPropertiesCollection::NamedItem(const nsAString& aName,
-                                    nsIDOMNode** aResult)
-{
-  *aResult = nullptr;
-  return NS_OK;
-}
-
-Element*
-HTMLPropertiesCollection::GetElementAt(uint32_t aIndex)
-{
-  EnsureFresh();
-  return mProperties.SafeElementAt(aIndex);
-}
-
-nsINode*
-HTMLPropertiesCollection::GetParentObject()
-{
-  return mRoot;
-}
-
-PropertyNodeList*
-HTMLPropertiesCollection::NamedItem(const nsAString& aName)
-{
-  EnsureFresh();
-
-  PropertyNodeList* propertyList = mNamedItemEntries.GetWeak(aName);
-  if (!propertyList) {
-    RefPtr<PropertyNodeList> newPropertyList =
-      new PropertyNodeList(this, mRoot, aName);
-    mNamedItemEntries.Put(aName, newPropertyList);
-    propertyList = newPropertyList;
-  }
-  return propertyList;
-}
-
-void
-HTMLPropertiesCollection::AttributeChanged(nsIDocument *aDocument, Element* aElement,
-                                           int32_t aNameSpaceID, nsIAtom* aAttribute,
-                                           int32_t aModType,
-                                           const nsAttrValue* aOldValue)
-{
-  mIsDirty = true;
-}
-
-void
-HTMLPropertiesCollection::ContentAppended(nsIDocument* aDocument, nsIContent* aContainer,
-                                          nsIContent* aFirstNewContent,
-                                          int32_t aNewIndexInContainer)
-{
-  mIsDirty = true;
-}
-
-void
-HTMLPropertiesCollection::ContentInserted(nsIDocument *aDocument,
-                                          nsIContent* aContainer,
-                                          nsIContent* aChild,
-                                          int32_t aIndexInContainer)
-{
-  mIsDirty = true;
-}
-
-void
-HTMLPropertiesCollection::ContentRemoved(nsIDocument *aDocument,
-                                         nsIContent* aContainer,
-                                         nsIContent* aChild,
-                                         int32_t aIndexInContainer,
-                                         nsIContent* aPreviousSibling)
-{
-  mIsDirty = true;
-}
-
-void
-HTMLPropertiesCollection::EnsureFresh()
-{
-  if (mDoc && !mIsDirty) {
-    return;
-  }
-  mIsDirty = false;
-
-  mProperties.Clear();
-  mNames->Clear();
-  // We don't clear NamedItemEntries because the PropertyNodeLists must be live.
-  for (auto iter = mNamedItemEntries.Iter(); !iter.Done(); iter.Next()) {
-    iter.UserData()->SetDirty();
-  }
-  if (!mRoot->HasAttr(kNameSpaceID_None, nsGkAtoms::itemscope)) {
-    return;
-  }
-
-  CrawlProperties();
-  TreeOrderComparator comparator;
-  mProperties.Sort(comparator);
-
-  // Create the names DOMStringList
-  uint32_t count = mProperties.Length();
-  for (uint32_t i = 0; i < count; ++i) {
-    const nsAttrValue* attr = mProperties.ElementAt(i)->GetParsedAttr(nsGkAtoms::itemprop); 
-    for (uint32_t i = 0; i < attr->GetAtomCount(); i++) {
-      nsDependentAtomString propName(attr->AtomAt(i));
-      bool contains = mNames->ContainsInternal(propName);
-      if (!contains) {
-        mNames->Add(propName);
-      }
-    }
-  }
-}
-
-static Element*
-GetElementByIdForConnectedSubtree(nsIContent* aContent, const nsIAtom* aId)
-{
-  aContent = static_cast<nsIContent*>(aContent->SubtreeRoot());
-  do {
-    if (aContent->GetID() == aId) {
-      return aContent->AsElement();
-    }
-    aContent = aContent->GetNextNode();
-  } while(aContent);
-
-  return nullptr;
-}
-
-void
-HTMLPropertiesCollection::CrawlProperties()
-{
-  nsIDocument* doc = mRoot->GetUncomposedDoc();
-
-  const nsAttrValue* attr = mRoot->GetParsedAttr(nsGkAtoms::itemref);
-  if (attr) {
-    for (uint32_t i = 0; i < attr->GetAtomCount(); i++) {
-      nsIAtom* ref = attr->AtomAt(i);
-      Element* element;
-      if (doc) {
-        element = doc->GetElementById(nsDependentAtomString(ref));
-      } else {
-        element = GetElementByIdForConnectedSubtree(mRoot, ref);
-      }
-      if (element && element != mRoot) {
-        CrawlSubtree(element);
-      }
-    }
-  }
-
-  CrawlSubtree(mRoot);
-}
-
-void
-HTMLPropertiesCollection::CrawlSubtree(Element* aElement)
-{
-  nsIContent* aContent = aElement;
-  while (aContent) {
-    // We must check aContent against mRoot because 
-    // an element must not be its own property
-    if (aContent == mRoot || !aContent->IsHTMLElement()) {
-      // Move on to the next node in the tree
-      aContent = aContent->GetNextNode(aElement);
-    } else {
-      MOZ_ASSERT(aContent->IsElement(), "IsHTMLElement() returned true!");
-      Element* element = aContent->AsElement();
-      if (element->HasAttr(kNameSpaceID_None, nsGkAtoms::itemprop) &&
-          !mProperties.Contains(element)) {
-        mProperties.AppendElement(static_cast<nsGenericHTMLElement*>(element));
-      }
-
-      if (element->HasAttr(kNameSpaceID_None, nsGkAtoms::itemscope)) {
-        aContent = element->GetNextNonChildNode(aElement);
-      } else {
-        aContent = element->GetNextNode(aElement);
-      }
-    }
-  }
-}
-
-void
-HTMLPropertiesCollection::GetSupportedNames(nsTArray<nsString>& aNames)
-{
-  EnsureFresh();
-  mNames->CopyList(aNames);
-}
-
-PropertyNodeList::PropertyNodeList(HTMLPropertiesCollection* aCollection,
-                                   nsIContent* aParent, const nsAString& aName)
-  : mName(aName),
-    mDoc(aParent->GetUncomposedDoc()),
-    mCollection(aCollection),
-    mParent(aParent),
-    mIsDirty(true)
-{
-  if (mDoc) {
-    mDoc->AddMutationObserver(this);
-  }
-}
-
-PropertyNodeList::~PropertyNodeList()
-{
-  if (mDoc) {
-    mDoc->RemoveMutationObserver(this);
-  }
-}
-
-void
-PropertyNodeList::SetDocument(nsIDocument* aDoc)
-{
-  if (mDoc) {
-    mDoc->RemoveMutationObserver(this);
-  }
-  mDoc = aDoc;
-  if (mDoc) {
-    mDoc->AddMutationObserver(this);
-  }
-  mIsDirty = true;
-}
-
-NS_IMETHODIMP
-PropertyNodeList::GetLength(uint32_t* aLength)
-{
-  EnsureFresh();
-  *aLength = mElements.Length();
-  return NS_OK;
-}
-
-NS_IMETHODIMP
-PropertyNodeList::Item(uint32_t aIndex, nsIDOMNode** aReturn)
-{
-  EnsureFresh();
-  nsINode* element = mElements.SafeElementAt(aIndex);
-  if (!element) {
-    *aReturn = nullptr;
-    return NS_OK;
-  }
-  return CallQueryInterface(element, aReturn);
-}
-
-nsIContent*
-PropertyNodeList::Item(uint32_t aIndex)
-{
-  EnsureFresh();
-  return mElements.SafeElementAt(aIndex);
-}
-
-int32_t
-PropertyNodeList::IndexOf(nsIContent* aContent)
-{
-  EnsureFresh();
-  return mElements.IndexOf(aContent);
-}
-
-nsINode*
-PropertyNodeList::GetParentObject()
-{
-  return mParent;
-}
-
-JSObject*
-PropertyNodeList::WrapObject(JSContext *cx, JS::Handle<JSObject*> aGivenProto)
-{
-  return PropertyNodeListBinding::Wrap(cx, this, aGivenProto);
-}
-
-NS_IMPL_CYCLE_COLLECTION_CLASS(PropertyNodeList)
-
-NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(PropertyNodeList)
-  // SetDocument(nullptr) ensures that we remove ourselves as a mutation observer
-  tmp->SetDocument(nullptr);
-  NS_IMPL_CYCLE_COLLECTION_UNLINK(mParent)
-  NS_IMPL_CYCLE_COLLECTION_UNLINK(mCollection)
-  NS_IMPL_CYCLE_COLLECTION_UNLINK(mElements)
-  NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER
-NS_IMPL_CYCLE_COLLECTION_UNLINK_END
-NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(PropertyNodeList)
-  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mDoc)
-  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mParent)
-  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mCollection)
-  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mElements)
-  NS_IMPL_CYCLE_COLLECTION_TRAVERSE_SCRIPT_OBJECTS
-NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
-NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(PropertyNodeList)
-  NS_IMPL_CYCLE_COLLECTION_TRACE_PRESERVED_WRAPPER
-NS_IMPL_CYCLE_COLLECTION_TRACE_END
-
-NS_IMPL_CYCLE_COLLECTING_ADDREF(PropertyNodeList)
-NS_IMPL_CYCLE_COLLECTING_RELEASE(PropertyNodeList)
-
-NS_INTERFACE_TABLE_HEAD(PropertyNodeList)
-    NS_WRAPPERCACHE_INTERFACE_TABLE_ENTRY
-    NS_INTERFACE_TABLE(PropertyNodeList,
-                       nsIDOMNodeList,
-                       nsINodeList,
-                       nsIMutationObserver)
-    NS_INTERFACE_TABLE_TO_MAP_SEGUE_CYCLE_COLLECTION(PropertyNodeList)
-NS_INTERFACE_MAP_END
-
-void
-PropertyNodeList::GetValues(JSContext* aCx, nsTArray<JS::Value >& aResult,
-                            ErrorResult& aError)
-{
-  EnsureFresh();
-
-  JS::Rooted<JSObject*> wrapper(aCx, GetWrapper());
-  JSAutoCompartment ac(aCx, wrapper);
-  uint32_t length = mElements.Length();
-  for (uint32_t i = 0; i < length; ++i) {
-    JS::Rooted<JS::Value> v(aCx);
-    mElements.ElementAt(i)->GetItemValue(aCx, wrapper, &v, aError);
-    if (aError.Failed()) {
-      return;
-    }
-    aResult.AppendElement(v);
-  }
-}
-
-void
-PropertyNodeList::AttributeChanged(nsIDocument* aDocument, Element* aElement,
-                                   int32_t aNameSpaceID, nsIAtom* aAttribute,
-                                   int32_t aModType,
-                                   const nsAttrValue* aOldValue)
-{
-  mIsDirty = true;
-}
-
-void
-PropertyNodeList::ContentAppended(nsIDocument* aDocument, nsIContent* aContainer,
-                                  nsIContent* aFirstNewContent,
-                                  int32_t aNewIndexInContainer)
-{
-  mIsDirty = true;
-}
-
-void
-PropertyNodeList::ContentInserted(nsIDocument* aDocument,
-                                  nsIContent* aContainer,
-                                  nsIContent* aChild,
-                                  int32_t aIndexInContainer)
-{
-  mIsDirty = true;
-}
-
-void
-PropertyNodeList::ContentRemoved(nsIDocument* aDocument,
-                                 nsIContent* aContainer,
-                                 nsIContent* aChild,
-                                 int32_t aIndexInContainer,
-                                 nsIContent* aPreviousSibling)
-{
-  mIsDirty = true;
-}
-
-void
-PropertyNodeList::EnsureFresh()
-{
-  if (mDoc && !mIsDirty) {
-    return;
-  }
-  mIsDirty = false;
-
-  mCollection->EnsureFresh();
-  Clear();
-
-  uint32_t count = mCollection->mProperties.Length();
-  for (uint32_t i = 0; i < count; ++i) {
-    nsGenericHTMLElement* element = mCollection->mProperties.ElementAt(i);
-    const nsAttrValue* attr = element->GetParsedAttr(nsGkAtoms::itemprop);
-    if (attr->Contains(mName)) {
-      AppendElement(element);
-    }
-  }
-}
-
-PropertyStringList::PropertyStringList(HTMLPropertiesCollection* aCollection)
-  : DOMStringList()
-  , mCollection(aCollection)
-{ }
-
-PropertyStringList::~PropertyStringList()
-{ }
-
-NS_IMPL_CYCLE_COLLECTION_INHERITED(PropertyStringList, DOMStringList,
-                                   mCollection)
-
-NS_IMPL_ADDREF_INHERITED(PropertyStringList, DOMStringList)
-NS_IMPL_RELEASE_INHERITED(PropertyStringList, DOMStringList)
-
-NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(PropertyStringList)
-NS_INTERFACE_MAP_END_INHERITING(DOMStringList)
-
-void
-PropertyStringList::EnsureFresh()
-{
-  MOZ_ASSERT(NS_IsMainThread());
-
-  mCollection->EnsureFresh();
-}
-
-bool
-PropertyStringList::ContainsInternal(const nsAString& aString)
-{
-  // This method should not call EnsureFresh, otherwise we may become stuck in an infinite loop.
-  return mNames.Contains(aString);
-}
-
-} // namespace dom
-} // namespace mozilla

deleted file mode 100644
--- a/dom/html/HTMLPropertiesCollection.h
+++ /dev/null
@@ -1,218 +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 HTMLPropertiesCollection_h_
-#define HTMLPropertiesCollection_h_
-
-#include "mozilla/Attributes.h"
-#include "mozilla/dom/DOMStringList.h"
-#include "nsCycleCollectionParticipant.h"
-#include "nsAutoPtr.h"
-#include "nsCOMArray.h"
-#include "nsIMutationObserver.h"
-#include "nsStubMutationObserver.h"
-#include "nsBaseHashtable.h"
-#include "nsINodeList.h"
-#include "nsIHTMLCollection.h"
-#include "nsHashKeys.h"
-#include "nsRefPtrHashtable.h"
-#include "nsGenericHTMLElement.h"
-
-class nsIDocument;
-class nsINode;
-
-namespace mozilla {
-namespace dom {
-
-class HTMLPropertiesCollection;
-class PropertyNodeList;
-class Element;
-
-class PropertyStringList : public DOMStringList
-{
-public:
-  explicit PropertyStringList(HTMLPropertiesCollection* aCollection);
-  NS_DECL_ISUPPORTS_INHERITED
-  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(PropertyStringList, DOMStringList)
-
-  bool ContainsInternal(const nsAString& aString);
-
-protected:
-  virtual ~PropertyStringList();
-
-  virtual void EnsureFresh() override;
-
-  RefPtr<HTMLPropertiesCollection> mCollection;
-};
-
-class HTMLPropertiesCollection final : public nsIHTMLCollection,
-                                       public nsStubMutationObserver,
-                                       public nsWrapperCache
-{
-  friend class PropertyNodeList;
-  friend class PropertyStringList;
-public:
-  explicit HTMLPropertiesCollection(nsGenericHTMLElement* aRoot);
-
-  // nsWrapperCache
-  using nsWrapperCache::GetWrapperPreserveColor;
-  using nsWrapperCache::GetWrapper;
-  virtual JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;
-protected:
-  virtual ~HTMLPropertiesCollection();
-
-  virtual JSObject* GetWrapperPreserveColorInternal() override
-  {
-    return nsWrapperCache::GetWrapperPreserveColor();
-  }
-public:
-
-  virtual Element* GetElementAt(uint32_t aIndex) override;
-
-  void SetDocument(nsIDocument* aDocument);
-  nsINode* GetParentObject() override;
-
-  virtual Element*
-  GetFirstNamedElement(const nsAString& aName, bool& aFound) override
-  {
-    // HTMLPropertiesCollection.namedItem and the named getter call the
-    // NamedItem that returns a PropertyNodeList, calling
-    // HTMLCollection.namedItem doesn't make sense so this returns null.
-    aFound = false;
-    return nullptr;
-  }
-  PropertyNodeList* NamedItem(const nsAString& aName);
-  PropertyNodeList* NamedGetter(const nsAString& aName, bool& aFound)
-  {
-    aFound = IsSupportedNamedProperty(aName);
-    return aFound ? NamedItem(aName) : nullptr;
-  }
-  DOMStringList* Names()
-  {
-    EnsureFresh();
-    return mNames;
-  }
-  virtual void GetSupportedNames(nsTArray<nsString>& aNames) override;
-
-  NS_DECL_NSIDOMHTMLCOLLECTION
-
-  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
-
-  NS_DECL_NSIMUTATIONOBSERVER_ATTRIBUTECHANGED
-  NS_DECL_NSIMUTATIONOBSERVER_CONTENTAPPENDED
-  NS_DECL_NSIMUTATIONOBSERVER_CONTENTINSERTED
-  NS_DECL_NSIMUTATIONOBSERVER_CONTENTREMOVED
-
-  NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS_AMBIGUOUS(HTMLPropertiesCollection,
-                                                         nsIHTMLCollection)
-
-protected:
-  // Make sure this collection is up to date, in case the DOM has been mutated.
-  void EnsureFresh();
-
-  // Crawl the properties of mRoot, following any itemRefs it may have
-  void CrawlProperties();
-
-  // Crawl startNode and its descendants, looking for items
-  void CrawlSubtree(Element* startNode);
-
-  bool IsSupportedNamedProperty(const nsAString& aName)
-  {
-    EnsureFresh();
-    return mNames->ContainsInternal(aName);
-  }
-
-  // the items that make up this collection
-  nsTArray<RefPtr<nsGenericHTMLElement> > mProperties;
-
-  // the itemprop attribute of the properties
-  RefPtr<PropertyStringList> mNames;
-
-  // The cached PropertyNodeLists that are NamedItems of this collection
-  nsRefPtrHashtable<nsStringHashKey, PropertyNodeList> mNamedItemEntries;
-
-  // The element this collection is rooted at
-  RefPtr<nsGenericHTMLElement> mRoot;
-
-  // The document mRoot is in, if any
-  nsCOMPtr<nsIDocument> mDoc;
-
-  // True if there have been DOM modifications since the last EnsureFresh call.
-  bool mIsDirty;
-};
-
-class PropertyNodeList final : public nsINodeList,
-                               public nsStubMutationObserver
-{
-public:
-  PropertyNodeList(HTMLPropertiesCollection* aCollection,
-                   nsIContent* aRoot, const nsAString& aName);
-
-  virtual JSObject* WrapObject(JSContext *cx, JS::Handle<JSObject*> aGivenProto) override;
-
-  void SetDocument(nsIDocument* aDocument);
-
-  void GetValues(JSContext* aCx, nsTArray<JS::Value >& aResult,
-                 ErrorResult& aError);
-
-  virtual nsIContent* Item(uint32_t aIndex) override;
-
-  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
-
-  NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS_AMBIGUOUS(PropertyNodeList,
-                                                         nsINodeList)
-  NS_DECL_NSIDOMNODELIST
-
-  NS_DECL_NSIMUTATIONOBSERVER_ATTRIBUTECHANGED
-  NS_DECL_NSIMUTATIONOBSERVER_CONTENTAPPENDED
-  NS_DECL_NSIMUTATIONOBSERVER_CONTENTINSERTED
-  NS_DECL_NSIMUTATIONOBSERVER_CONTENTREMOVED
-
-  // nsINodeList interface
-  virtual int32_t IndexOf(nsIContent* aContent) override;
-  virtual nsINode* GetParentObject() override;
-
-  void AppendElement(nsGenericHTMLElement* aElement)
-  {
-    mElements.AppendElement(aElement);
-  }
-
-  void Clear()
-  {
-    mElements.Clear();
-  }
-
-  void SetDirty() { mIsDirty = true; }
-
-protected:
-  virtual ~PropertyNodeList();
-
-  // Make sure this list is up to date, in case the DOM has been mutated.
-  void EnsureFresh();
-
-  // the the name that this list corresponds to
-  nsString mName;
-
-  // the document mParent is in, if any
-  nsCOMPtr<nsIDocument> mDoc;
-
-  // the collection that this list is a named item of
-  RefPtr<HTMLPropertiesCollection> mCollection;
-
-  // the node this list is rooted at
-  nsCOMPtr<nsINode> mParent;
-
-  // the properties that make up this list
-  nsTArray<RefPtr<nsGenericHTMLElement> > mElements;
-
-  // True if there have been DOM modifications since the last EnsureFresh call. 
-  bool mIsDirty;
-};
-
-} // namespace dom
-} // namespace mozilla
-
-#endif // HTMLPropertiesCollection_h_

--- a/dom/html/HTMLSharedObjectElement.cpp
+++ b/dom/html/HTMLSharedObjectElement.cpp
@@ -36,36 +36,16 @@ HTMLSharedObjectElement::HTMLSharedObjec
 {
   RegisterActivityObserver();
   SetIsNetworkCreated(aFromParser == FROM_PARSER_NETWORK);
 
   // By default we're in the loading state
   AddStatesSilently(NS_EVENT_STATE_LOADING);
 }
 
-void
-HTMLSharedObjectElement::GetItemValueText(DOMString& aValue)
-{
-  if (mNodeInfo->Equals(nsGkAtoms::applet)) {
-    nsGenericHTMLElement::GetItemValueText(aValue);
-  } else {
-    GetSrc(aValue);
-  }
-}
-
-void
-HTMLSharedObjectElement::SetItemValueText(const nsAString& aValue)
-{
-  if (mNodeInfo->Equals(nsGkAtoms::applet)) {
-    nsGenericHTMLElement::SetItemValueText(aValue);
-  } else {
-    SetSrc(aValue);
-  }
-}
-
 HTMLSharedObjectElement::~HTMLSharedObjectElement()
 {
 #ifdef XP_MACOSX
   HTMLObjectElement::OnFocusBlurPlugin(this, false);
 #endif
   UnregisterActivityObserver();
   DestroyImageLoadingContent();
 }

--- a/dom/html/HTMLSharedObjectElement.h
+++ b/dom/html/HTMLSharedObjectElement.h
@@ -207,19 +207,16 @@ private:
   }
 
   nsContentPolicyType GetContentPolicyType() const override;
 
   // mIsDoneAddingChildren is only really used for <applet>.  This boolean is
   // always true for <embed>, per the documentation in nsIContent.h.
   bool mIsDoneAddingChildren;
 
-  virtual void GetItemValueText(DOMString& text) override;
-  virtual void SetItemValueText(const nsAString& text) override;
-
   virtual JSObject* WrapNode(JSContext *aCx, JS::Handle<JSObject*> aGivenProto) override;
 
   static void MapAttributesIntoRule(const nsMappedAttributes* aAttributes,
                                     nsRuleData* aData);
 
   /**
    * Decides whether we should load embed node content.
    *

--- a/dom/html/HTMLSourceElement.cpp
+++ b/dom/html/HTMLSourceElement.cpp
@@ -141,28 +141,16 @@ HTMLSourceElement::AfterSetAttr(int32_t 
       }
     }
   }
 
   return nsGenericHTMLElement::AfterSetAttr(aNameSpaceID, aName,
                                             aValue, aNotify);
 }
 
-void
-HTMLSourceElement::GetItemValueText(DOMString& aValue)
-{
-  GetSrc(aValue);
-}
-
-void
-HTMLSourceElement::SetItemValueText(const nsAString& aValue)
-{
-  SetSrc(aValue);
-}
-
 nsresult
 HTMLSourceElement::BindToTree(nsIDocument *aDocument,
                               nsIContent *aParent,
                               nsIContent *aBindingParent,
                               bool aCompileEventHandlers)
 {
   nsresult rv = nsGenericHTMLElement::BindToTree(aDocument,
                                                  aParent,

--- a/dom/html/HTMLSourceElement.h
+++ b/dom/html/HTMLSourceElement.h
@@ -103,24 +103,20 @@ public:
   }
 
 protected:
   virtual ~HTMLSourceElement();
 
   virtual JSObject* WrapNode(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;
 
 protected:
-  virtual void GetItemValueText(DOMString& text) override;
-  virtual void SetItemValueText(const nsAString& text) override;
-
   virtual nsresult AfterSetAttr(int32_t aNameSpaceID, nsIAtom* aName,
                                 const nsAttrValue* aValue,
                                 bool aNotify) override;
 
-
 private:
   RefPtr<nsMediaList> mMediaList;
   RefPtr<MediaSource> mSrcMediaSource;
 
   // Generates a new nsMediaList using the given input
   void UpdateMediaList(const nsAttrValue* aValue);
 };
 

--- a/dom/html/HTMLTimeElement.cpp
+++ b/dom/html/HTMLTimeElement.cpp
@@ -27,28 +27,10 @@ HTMLTimeElement::~HTMLTimeElement()
 NS_IMPL_ELEMENT_CLONE(HTMLTimeElement)
 
 JSObject*
 HTMLTimeElement::WrapNode(JSContext* cx, JS::Handle<JSObject*> aGivenProto)
 {
   return HTMLTimeElementBinding::Wrap(cx, this, aGivenProto);
 }
 
-void
-HTMLTimeElement::GetItemValueText(DOMString& text)
-{
-  if (HasAttr(kNameSpaceID_None, nsGkAtoms::datetime)) {
-    GetDateTime(text);
-  } else {
-    ErrorResult rv;
-    GetTextContentInternal(text, rv);
-  }
-}
-
-void
-HTMLTimeElement::SetItemValueText(const nsAString& text)
-{
-  ErrorResult rv;
-  SetDateTime(text, rv);
-}
-
 } // namespace dom
 } // namespace mozilla

--- a/dom/html/HTMLTimeElement.h
+++ b/dom/html/HTMLTimeElement.h
@@ -27,18 +27,16 @@ public:
     GetHTMLAttr(nsGkAtoms::datetime, aDateTime);
   }
 
   void SetDateTime(const nsAString& aDateTime, ErrorResult& aError)
   {
     SetHTMLAttr(nsGkAtoms::datetime, aDateTime, aError);
   }
 
-  virtual void GetItemValueText(DOMString& text) override;
-  virtual void SetItemValueText(const nsAString& text) override;
   virtual nsresult Clone(mozilla::dom::NodeInfo* aNodeInfo, nsINode** aResult) const override;
 
 protected:
   virtual JSObject* WrapNode(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;
 };
 
 } // namespace dom
 } // namespace mozilla

--- a/dom/html/HTMLTrackElement.h
+++ b/dom/html/HTMLTrackElement.h
@@ -88,27 +88,16 @@ public:
 
   uint16_t ReadyState() const;
   void SetReadyState(uint16_t aReadyState);
 
   TextTrack* GetTrack();
 
   virtual nsresult Clone(mozilla::dom::NodeInfo* aNodeInfo, nsINode** aResult) const override;
 
-  // For Track, ItemValue reflects the src attribute
-  virtual void GetItemValueText(DOMString& aText) override
-  {
-    GetSrc(aText);
-  }
-  virtual void SetItemValueText(const nsAString& aText) override
-  {
-    ErrorResult rv;
-    SetSrc(aText, rv);
-  }
-
   // Override ParseAttribute() to convert kind strings to enum values.
   virtual bool ParseAttribute(int32_t aNamespaceID,
                               nsIAtom* aAttribute,
                               const nsAString& aValue,
                               nsAttrValue& aResult) override;
 
   // Override BindToTree() so that we can trigger a load when we become
   // the child of a media element.

--- a/dom/html/moz.build
+++ b/dom/html/moz.build
@@ -23,17 +23,16 @@ XPIDL_SOURCES += [
     'nsIImageDocument.idl',
     'nsIMenuBuilder.idl',
     'nsIPhonetic.idl',
 ]
 
 XPIDL_MODULE = 'content_html'
 
 EXPORTS += [
-    'HTMLPropertiesCollection.h',
     'nsFormSubmission.h',
     'nsGenericHTMLElement.h',
     'nsHTMLDNSPrefetch.h',
     'nsIConstraintValidation.h',
     'nsIForm.h',
     'nsIFormControl.h',
     'nsIFormProcessor.h',
     'nsIHTMLCollection.h',
@@ -163,17 +162,16 @@ UNIFIED_SOURCES += [
     'HTMLOptGroupElement.cpp',
     'HTMLOptionElement.cpp',
     'HTMLOptionsCollection.cpp',
     'HTMLOutputElement.cpp',
     'HTMLParagraphElement.cpp',
     'HTMLPictureElement.cpp',
     'HTMLPreElement.cpp',
     'HTMLProgressElement.cpp',
-    'HTMLPropertiesCollection.cpp',
     'HTMLScriptElement.cpp',
     'HTMLSelectElement.cpp',
     'HTMLShadowElement.cpp',
     'HTMLSharedElement.cpp',
     'HTMLSharedListElement.cpp',
     'HTMLSharedObjectElement.cpp',
     'HTMLSourceElement.cpp',
     'HTMLSpanElement.cpp',

--- a/dom/html/nsGenericHTMLElement.cpp
+++ b/dom/html/nsGenericHTMLElement.cpp
@@ -89,17 +89,16 @@
 #include "HTMLMenuElement.h"
 #include "nsDOMMutationObserver.h"
 #include "mozilla/Preferences.h"
 #include "mozilla/dom/FromParser.h"
 #include "mozilla/dom/Link.h"
 #include "mozilla/dom/UndoManager.h"
 #include "mozilla/BloomFilter.h"
 
-#include "HTMLPropertiesCollection.h"
 #include "nsVariant.h"
 #include "nsDOMTokenList.h"
 #include "nsThreadUtils.h"
 #include "nsTextFragment.h"
 #include "mozilla/dom/BindingUtils.h"
 #include "mozilla/dom/TouchEvent.h"
 #include "mozilla/ErrorResult.h"
 #include "nsHTMLDocument.h"
@@ -542,23 +541,16 @@ nsGenericHTMLElement::BindToTree(nsIDocu
                                  bool aCompileEventHandlers)
 {
   nsresult rv = nsGenericHTMLElementBase::BindToTree(aDocument, aParent,
                                                      aBindingParent,
                                                      aCompileEventHandlers);
   NS_ENSURE_SUCCESS(rv, rv);
 
   if (aDocument) {
-    if (HasProperties()) {
-      HTMLPropertiesCollection* properties = 
-        static_cast<HTMLPropertiesCollection*>(GetProperty(nsGkAtoms::microdataProperties));
-      if (properties) {
-        properties->SetDocument(aDocument);
-      }
-    }
     RegAccessKey();
     if (HasName()) {
       aDocument->
         AddToNameTable(this, GetParsedAttr(nsGkAtoms::name)->GetAtomValue());
     }
 
     if (HasFlag(NODE_IS_EDITABLE) && GetContentEditableValue() == eTrue) {
       nsCOMPtr<nsIHTMLDocument> htmlDocument = do_QueryInterface(aDocument);
@@ -573,24 +565,16 @@ nsGenericHTMLElement::BindToTree(nsIDocu
 
 void
 nsGenericHTMLElement::UnbindFromTree(bool aDeep, bool aNullParent)
 {
   if (IsInUncomposedDoc()) {
     UnregAccessKey();
   }
   
-  if(HasProperties()) {
-    HTMLPropertiesCollection* properties = 
-      static_cast<HTMLPropertiesCollection*>(GetProperty(nsGkAtoms::microdataProperties));
-    if (properties) {
-      properties->SetDocument(nullptr);
-    }
-  }
-
   RemoveFromNameTable();
 
   if (GetContentEditableValue() == eTrue) {
     //XXXsmaug Fix this for Shadow DOM, bug 1066965.
     nsCOMPtr<nsIHTMLDocument> htmlDocument = do_QueryInterface(GetUncomposedDoc());
     if (htmlDocument) {
       htmlDocument->ChangeContentEditableCount(this, -1);
     }
@@ -1023,20 +1007,17 @@ nsGenericHTMLElement::ParseAttribute(int
       return true;
     }
 
     if (aAttribute == nsGkAtoms::contenteditable) {
       aResult.ParseAtom(aValue);
       return true;
     }
 
-    if (aAttribute == nsGkAtoms::itemref ||
-        aAttribute == nsGkAtoms::itemprop ||
-        aAttribute == nsGkAtoms::itemtype ||
-        aAttribute == nsGkAtoms::rel) {
+    if (aAttribute == nsGkAtoms::rel) {
       aResult.ParseAtomArray(aValue);
       return true;
     }
   }
 
   return nsGenericHTMLElementBase::ParseAttribute(aNamespaceID, aAttribute,
                                                   aValue, aResult);
 }
@@ -3114,144 +3095,16 @@ nsGenericHTMLFormElementWithState::Resto
 }
 
 void
 nsGenericHTMLFormElementWithState::NodeInfoChanged(mozilla::dom::NodeInfo* aOldNodeInfo)
 {
   mStateKey.SetIsVoid(true);
 }
 
-void
-nsGenericHTMLElement::GetItemValue(JSContext* aCx, JSObject* aScope,
-                                   JS::MutableHandle<JS::Value> aRetval,
-                                   ErrorResult& aError)
-{
-  JS::Rooted<JSObject*> scope(aCx, aScope);
-  if (!HasAttr(kNameSpaceID_None, nsGkAtoms::itemprop)) {
-    aRetval.setNull();
-    return;
-  }
-
-  if (ItemScope()) {
-    JS::Rooted<JS::Value> v(aCx);
-    JSAutoCompartment ac(aCx, scope);
-    if (!mozilla::dom::WrapObject(aCx, this, aRetval)) {
-      aError.Throw(NS_ERROR_FAILURE);
-    }
-    return;
-  }
-
-  DOMString string;
-  GetItemValueText(string);
-  if (!xpc::NonVoidStringToJsval(aCx, string, aRetval)) {
-    aError.Throw(NS_ERROR_FAILURE);
-  }
-}
-
-NS_IMETHODIMP
-nsGenericHTMLElement::GetItemValue(nsIVariant** aValue)
-{
-  nsCOMPtr<nsIWritableVariant> out = new nsVariant();
-
-  if (!HasAttr(kNameSpaceID_None, nsGkAtoms::itemprop)) {
-    out->SetAsEmpty();
-    out.forget(aValue);
-    return NS_OK;
-  }
-
-  if (ItemScope()) {
-    out->SetAsISupports(static_cast<nsIContent*>(this));
-  } else {
-    DOMString string;
-    GetItemValueText(string);
-    nsString xpcomString;
-    string.ToString(xpcomString);
-    out->SetAsAString(xpcomString);
-  }
-
-  out.forget(aValue);
-  return NS_OK;
-}
-
-void
-nsGenericHTMLElement::SetItemValue(JSContext* aCx, JS::Value aValue,
-                                   ErrorResult& aError)
-{
-  if (!HasAttr(kNameSpaceID_None, nsGkAtoms::itemprop) ||
-      HasAttr(kNameSpaceID_None, nsGkAtoms::itemscope)) {
-    aError.Throw(NS_ERROR_DOM_INVALID_ACCESS_ERR);
-    return;
-  }
-
-  nsAutoString string;
-  JS::Rooted<JS::Value> value(aCx, aValue);
-  if (!ConvertJSValueToString(aCx, value, eStringify, eStringify, string)) {
-    aError.Throw(NS_ERROR_UNEXPECTED);
-    return;
-  }
-  SetItemValueText(string);
-}
-
-NS_IMETHODIMP
-nsGenericHTMLElement::SetItemValue(nsIVariant* aValue)
-{
-  if (!HasAttr(kNameSpaceID_None, nsGkAtoms::itemprop) ||
-      HasAttr(kNameSpaceID_None, nsGkAtoms::itemscope)) {
-    return NS_ERROR_DOM_INVALID_ACCESS_ERR;
-  }
-
-  nsAutoString string;
-  aValue->GetAsAString(string);
-  SetItemValueText(string);
-  return NS_OK;
-}
-
-void
-nsGenericHTMLElement::GetItemValueText(DOMString& text)
-{
-  ErrorResult rv;
-  GetTextContentInternal(text, rv);
-}
-
-void
-nsGenericHTMLElement::SetItemValueText(const nsAString& text)
-{
-  mozilla::ErrorResult rv;
-  SetTextContentInternal(text, rv);
-}
-
-static void
-HTMLPropertiesCollectionDestructor(void *aObject, nsIAtom *aProperty,
-                                   void *aPropertyValue, void *aData)
-{
-  HTMLPropertiesCollection* properties =
-    static_cast<HTMLPropertiesCollection*>(aPropertyValue);
-  NS_IF_RELEASE(properties);
-}
-
-HTMLPropertiesCollection*
-nsGenericHTMLElement::Properties()
-{
-  HTMLPropertiesCollection* properties =
-    static_cast<HTMLPropertiesCollection*>(GetProperty(nsGkAtoms::microdataProperties));
-  if (!properties) {
-     properties = new HTMLPropertiesCollection(this);
-     NS_ADDREF(properties);
-     SetProperty(nsGkAtoms::microdataProperties, properties, HTMLPropertiesCollectionDestructor);
-  }
-  return properties;
-}
-
-NS_IMETHODIMP
-nsGenericHTMLElement::GetProperties(nsISupports** aProperties)
-{
-  NS_ADDREF(*aProperties = static_cast<nsIHTMLCollection*>(Properties()));
-  return NS_OK;
-}
-
 nsSize
 nsGenericHTMLElement::GetWidthHeightForImage(RefPtr<imgRequestProxy>& aImageRequest)
 {
   nsSize size(0,0);
 
   nsIFrame* frame = GetPrimaryFrame(Flush_Layout);
 
   if (frame) {

--- a/dom/html/nsGenericHTMLElement.h
+++ b/dom/html/nsGenericHTMLElement.h
@@ -33,17 +33,16 @@ struct nsSize;
 namespace mozilla {
 class EventChainPostVisitor;
 class EventChainPreVisitor;
 class EventChainVisitor;
 class EventListenerManager;
 class EventStates;
 namespace dom {
 class HTMLFormElement;
-class HTMLPropertiesCollection;
 class HTMLMenuElement;
 } // namespace dom
 } // namespace mozilla
 
 typedef nsMappedAttributeElement nsGenericHTMLElementBase;
 
 /**
  * A common superclass for HTML elements
@@ -91,55 +90,16 @@ public:
   {
     GetHTMLEnumAttr(nsGkAtoms::dir, aDir);
   }
   void SetDir(const nsAString& aDir, mozilla::ErrorResult& aError)
   {
     SetHTMLAttr(nsGkAtoms::dir, aDir, aError);
   }
   already_AddRefed<nsDOMStringMap> Dataset();
-  bool ItemScope() const
-  {
-    return GetBoolAttr(nsGkAtoms::itemscope);
-  }
-  void SetItemScope(bool aItemScope, mozilla::ErrorResult& aError)
-  {
-    SetHTMLBoolAttr(nsGkAtoms::itemscope, aItemScope, aError);
-  }
-  nsDOMTokenList* ItemType()
-  {
-    return GetTokenList(nsGkAtoms::itemtype);
-  }
-  void GetItemId(nsString& aItemId)
-  {
-    GetHTMLURIAttr(nsGkAtoms::itemid, aItemId);
-  }
-  void SetItemId(const nsAString& aItemID, mozilla::ErrorResult& aError)
-  {
-    SetHTMLAttr(nsGkAtoms::itemid, aItemID, aError);
-  }
-  nsDOMTokenList* ItemRef()
-  {
-    return GetTokenList(nsGkAtoms::itemref);
-  }
-  nsDOMTokenList* ItemProp()
-  {
-    return GetTokenList(nsGkAtoms::itemprop);
-  }
-  mozilla::dom::HTMLPropertiesCollection* Properties();
-  void GetItemValue(JSContext* aCx, JSObject* aScope,
-                    JS::MutableHandle<JS::Value> aRetval,
-                    mozilla::ErrorResult& aError);
-  void GetItemValue(JSContext* aCx, JS::MutableHandle<JS::Value> aRetval,
-                    mozilla::ErrorResult& aError)
-  {
-    GetItemValue(aCx, GetWrapperPreserveColor(), aRetval, aError);
-  }
-  void SetItemValue(JSContext* aCx, JS::Value aValue,
-                    mozilla::ErrorResult& aError);
   bool Hidden() const
   {
     return GetBoolAttr(nsGkAtoms::hidden);
   }
   void SetHidden(bool aHidden, mozilla::ErrorResult& aError)
   {
     SetHTMLBoolAttr(nsGkAtoms::hidden, aHidden, aError);
   }
@@ -319,20 +279,16 @@ public:
   inline bool IsAnyOfHTMLElements(First aFirst, Args... aArgs) const
   {
     return IsNodeInternal(aFirst, aArgs...);
   }
 
 protected:
   virtual ~nsGenericHTMLElement() {}
 
-  // These methods are used to implement element-specific behavior of Get/SetItemValue
-  // when an element has @itemprop but no @itemscope.
-  virtual void GetItemValueText(mozilla::dom::DOMString& text);
-  virtual void SetItemValueText(const nsAString& text);
 public:
   virtual already_AddRefed<mozilla::dom::UndoManager> GetUndoManager() override;
   virtual bool UndoScope() override;
   virtual void SetUndoScope(bool aUndoScope, mozilla::ErrorResult& aError) override;
   // Callback for destructor of of dataset to ensure to null out weak pointer.
   nsresult ClearDataset();
 
   /**
@@ -388,60 +344,16 @@ public:
     SetHidden(aHidden, rv);
     return rv.StealNSResult();
   }
   NS_IMETHOD DOMBlur() final override {
     mozilla::ErrorResult rv;
     Blur(rv);
     return rv.StealNSResult();
   }
-  NS_IMETHOD GetItemScope(bool* aItemScope) final override {
-    *aItemScope = ItemScope();
-    return NS_OK;
-  }
-  NS_IMETHOD SetItemScope(bool aItemScope) final override {
-    mozilla::ErrorResult rv;
-    SetItemScope(aItemScope, rv);
-    return rv.StealNSResult();
-  }
-  NS_IMETHOD GetItemType(nsIVariant** aType) final override {
-    GetTokenList(nsGkAtoms::itemtype, aType);
-    return NS_OK;
-  }
-  NS_IMETHOD SetItemType(nsIVariant* aType) final override {
-    return SetTokenList(nsGkAtoms::itemtype, aType);
-  }
-  NS_IMETHOD GetItemId(nsAString& aId) final override {
-    nsString id;
-    GetItemId(id);
-    aId.Assign(id);
-    return NS_OK;
-  }
-  NS_IMETHOD SetItemId(const nsAString& aId) final override {
-    mozilla::ErrorResult rv;
-    SetItemId(aId, rv);
-    return rv.StealNSResult();
-  }
-  NS_IMETHOD GetProperties(nsISupports** aReturn) final override;
-  NS_IMETHOD GetItemValue(nsIVariant** aValue) final override;
-  NS_IMETHOD SetItemValue(nsIVariant* aValue) final override;
-  NS_IMETHOD GetItemRef(nsIVariant** aRef) final override {
-    GetTokenList(nsGkAtoms::itemref, aRef);
-    return NS_OK;
-  }
-  NS_IMETHOD SetItemRef(nsIVariant* aRef) final override {
-    return SetTokenList(nsGkAtoms::itemref, aRef);
-  }
-  NS_IMETHOD GetItemProp(nsIVariant** aProp) final override {
-    GetTokenList(nsGkAtoms::itemprop, aProp);
-    return NS_OK;
-  }
-  NS_IMETHOD SetItemProp(nsIVariant* aProp) final override {
-    return SetTokenList(nsGkAtoms::itemprop, aProp);
-  }
   NS_IMETHOD GetAccessKey(nsAString& aAccessKey) final override {
     nsString accessKey;
     GetAccessKey(accessKey);
     aAccessKey.Assign(accessKey);
     return NS_OK;
   }
   NS_IMETHOD SetAccessKey(const nsAString& aAccessKey) final override {
     mozilla::ErrorResult rv;

--- a/dom/html/nsHTMLDocument.cpp
+++ b/dom/html/nsHTMLDocument.cpp
@@ -1970,96 +1970,16 @@ nsHTMLDocument::UseExistingNameString(ns
 NS_IMETHODIMP
 nsHTMLDocument::GetElementsByName(const nsAString& aElementName,
                                   nsIDOMNodeList** aReturn)
 {
   *aReturn = GetElementsByName(aElementName).take();
   return NS_OK;
 }
 
-static bool MatchItems(nsIContent* aContent, int32_t aNameSpaceID, 
-                       nsIAtom* aAtom, void* aData)
-{
-  if (!aContent->IsHTMLElement()) {
-    return false;
-  }
-
-  nsGenericHTMLElement* elem = static_cast<nsGenericHTMLElement*>(aContent);
-  if (!elem->HasAttr(kNameSpaceID_None, nsGkAtoms::itemscope) ||
-      elem->HasAttr(kNameSpaceID_None, nsGkAtoms::itemprop)) {
-    return false;
-  }
-
-  nsTArray<nsCOMPtr<nsIAtom> >* tokens = static_cast<nsTArray<nsCOMPtr<nsIAtom> >*>(aData);
-  if (tokens->IsEmpty()) {
-    return true;
-  }
- 
-  const nsAttrValue* attr = elem->GetParsedAttr(nsGkAtoms::itemtype);
-  if (!attr)
-    return false;
-
-  for (uint32_t i = 0; i < tokens->Length(); i++) {
-    if (!attr->Contains(tokens->ElementAt(i), eCaseMatters)) {
-      return false;
-    }
-  }
-  return true;
-}
-
-static void DestroyTokens(void* aData)
-{
-  nsTArray<nsCOMPtr<nsIAtom> >* tokens = static_cast<nsTArray<nsCOMPtr<nsIAtom> >*>(aData);
-  delete tokens;
-}
-
-static void* CreateTokens(nsINode* aRootNode, const nsString* types)
-{
-  nsTArray<nsCOMPtr<nsIAtom> >* tokens = new nsTArray<nsCOMPtr<nsIAtom> >();
-  nsAString::const_iterator iter, end;
-  types->BeginReading(iter);
-  types->EndReading(end);
-  
-  // skip initial whitespace
-  while (iter != end && nsContentUtils::IsHTMLWhitespace(*iter)) {
-    ++iter;
-  }
-
-  // parse the tokens
-  while (iter != end) {
-    nsAString::const_iterator start(iter);
-
-    do {
-      ++iter;
-    } while (iter != end && !nsContentUtils::IsHTMLWhitespace(*iter));
-
-    tokens->AppendElement(NS_Atomize(Substring(start, iter)));
-
-    // skip whitespace
-    while (iter != end && nsContentUtils::IsHTMLWhitespace(*iter)) {
-      ++iter;
-    }
-  }
-  return tokens;
-}
-
-NS_IMETHODIMP
-nsHTMLDocument::GetItems(const nsAString& types, nsIDOMNodeList** aReturn)
-{
-  *aReturn = GetItems(types).take();
-  return NS_OK;
-}
-
-already_AddRefed<nsINodeList>
-nsHTMLDocument::GetItems(const nsAString& aTypeNames)
-{
-  return NS_GetFuncStringNodeList(this, MatchItems, DestroyTokens, CreateTokens,
-                                  aTypeNames);
-}
-
 void
 nsHTMLDocument::AddedForm()
 {
   ++mNumForms;
 }
 
 void
 nsHTMLDocument::RemovedForm()

--- a/dom/html/nsHTMLDocument.h
+++ b/dom/html/nsHTMLDocument.h
@@ -189,17 +189,16 @@ public:
     return nsHTMLDocument::GetForms();
   }
   nsIHTMLCollection* Scripts();
   already_AddRefed<nsContentList> GetElementsByName(const nsAString & aName)
   {
     return NS_GetFuncStringNodeList(this, MatchNameAttribute, nullptr,
                                     UseExistingNameString, aName);
   }
-  already_AddRefed<nsINodeList> GetItems(const nsAString& aTypeNames);
   already_AddRefed<nsIDocument> Open(JSContext* cx,
                                      const nsAString& aType,
                                      const nsAString& aReplace,
                                      mozilla::ErrorResult& rv);
   already_AddRefed<nsPIDOMWindowOuter>
   Open(JSContext* cx,
        const nsAString& aURL,
        const nsAString& aName,

--- a/dom/html/test/test_bug629801.html
+++ b/dom/html/test/test_bug629801.html
@@ -33,26 +33,16 @@ var t1 = document.getElementById("t1"),
     t3 = document.getElementById("t3"),
     t4 = document.createElement("time");
 
 // .dateTime IDL
 is(t1.dateTime, "", "dateTime is properly set to empty string if datetime attributeis absent");
 is(t2.dateTime, "2009-05-10", "dateTime is properly set to datetime attribute with datetime and no text content");
 is(t3.dateTime, "2009-05-10", "dateTime is properly set to datetime attribute with datetime and text content");
 
-// .itemValue getter for <time>'s microdata
-var times = document.getItems()[0];
-is(times.properties["a"][0].itemValue, "May 10th 2009", "itemValue getter with no datetime uses text content");
-is(times.properties["b"][0].itemValue, "2009-05-10", "itemValue getter with no text content uses datetime");
-is(times.properties["c"][0].itemValue, "2009-05-10", "itemValue getter with datetime and text content uses datetime");
-
-// .itemValue setter uses datetime vs. text content
-times.properties["a"][0].itemValue = "2009-05-10";
-is(times.properties["a"][0].dateTime, "2009-05-10", "setting itemValue updates datetime");
-
 // dateTime reflects datetime attribute
 reflectString({
   element: t4,
   attribute: "dateTime"
 });
 
 </script>
 </pre>

--- a/dom/html/test/test_bug763626.html
+++ b/dom/html/test/test_bug763626.html
@@ -10,17 +10,17 @@ https://bugzilla.mozilla.org/show_bug.cg
 <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
 
 <script type="application/javascript">
 
 SimpleTest.waitForExplicitFinish();
 
 function boom()
 {
-  var r = document.createElement("div").itemRef;
+  var r = document.createElement("iframe").sandbox;
   SpecialPowers.DOMWindowUtils.garbageCollect();
   is("" + r, "", "ToString should return empty string when element is gone");
   SimpleTest.finish();
 }
 
 </script>
 </head>
 

--- a/dom/html/test/test_bug839371.html
+++ b/dom/html/test/test_bug839371.html
@@ -27,25 +27,16 @@ https://bugzilla.mozilla.org/show_bug.cg
 var d1 = document.getElementById("d1"),
     d2 = document.createElement("data");
 
 // .value IDL
 is(d1.value, "9678AOU879", "value property reflects content attribute");
 d1.value = "123";
 is(d1.value, "123", "value property can be set via setter");
 
-// .itemValue getter for <data>'s microdata
-var data = document.getItems()[0];
-is(data.properties["product-id"][0].itemValue, "123", "itemValue getter reflects value attribute");
-
-// .itemValue setter uses value
-data.properties["product-id"][0].itemValue = "456";
-is(data.properties["product-id"][0].value, "456", "setting itemValue updates value");
-is(data.properties["product-id"][0].itemValue, "456", "setting itemValue updates itemValue");
-
 // .value reflects value attribute
 reflectString({
   element: d2,
   attribute: "value"
 });
 
 </script>
 </pre>

--- a/dom/interfaces/html/nsIDOMHTMLDocument.idl
+++ b/dom/interfaces/html/nsIDOMHTMLDocument.idl
@@ -25,17 +25,16 @@ interface nsIDOMHTMLDocument : nsIDOMDoc
   readonly attribute nsIDOMHTMLCollection images;
   readonly attribute nsIDOMHTMLCollection embeds;
   // mapped to attribute embeds for NS4 compat
   readonly attribute nsIDOMHTMLCollection plugins;
   readonly attribute nsIDOMHTMLCollection links;
   readonly attribute nsIDOMHTMLCollection forms;
   readonly attribute nsIDOMHTMLCollection scripts;
   nsIDOMNodeList            getElementsByName(in DOMString elementName);
-  nsIDOMNodeList  getItems([optional] in DOMString types);
 
   // If aContentType is not something supported by nsHTMLDocument and
   // the HTML content sink, trying to write to the document will
   // probably throw.
   // Pass aReplace = true to trigger a replacement of the previous
   // document in session history; pass false for normal history handling.
   [implicit_jscontext, optional_argc]
   nsISupports               open([optional] in DOMString aContentTypeOrUrl,

--- a/dom/interfaces/html/nsIDOMHTMLElement.idl
+++ b/dom/interfaces/html/nsIDOMHTMLElement.idl
@@ -23,26 +23,16 @@ interface nsIDOMHTMLMenuElement;
 interface nsIDOMHTMLElement : nsIDOMElement
 {
   // metadata attributes
            attribute DOMString        title;
            attribute DOMString        lang;
            attribute DOMString        dir;
   readonly attribute nsISupports      dataset;
 
-           attribute boolean                        itemScope;
-           attribute nsIVariant                     itemType;
-           attribute DOMString                      itemId;
-  readonly attribute nsISupports                    properties;
-  // The following attributes are really nsDOMTokenList, which has
-  // PutForwards, so we express them as nsIVariants to deal with this.
-           attribute nsIVariant                     itemValue;
-           attribute nsIVariant                     itemProp;
-           attribute nsIVariant                     itemRef;
-
   // user interaction
   /**
    * Indicates that the element is not yet, or is no longer, relevant.
    *
    * See <http://www.whatwg.org/html5/#the-hidden-attribute>.
    */
            attribute boolean          hidden;
   [binaryname(DOMClick)]

--- a/dom/tests/mochitest/general/test_interfaces.html
+++ b/dom/tests/mochitest/general/test_interfaces.html
@@ -621,18 +621,16 @@ var interfaceNamesInGlobalScope =
     "HTMLParamElement",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "HTMLPreElement",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "HTMLPictureElement",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "HTMLProgressElement",
 // IMPORTANT: Do not change this list without review from a DOM peer!
-    "HTMLPropertiesCollection",
-// 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!
     "HTMLShadowElement",
 // IMPORTANT: Do not change this list without review from a DOM peer!
@@ -951,18 +949,16 @@ var interfaceNamesInGlobalScope =
     {name: "PresentationSessionConnectEvent", disabled: true, permission: ["presentation"]},
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "ProcessingInstruction",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "ProgressEvent",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "Promise",
 // IMPORTANT: Do not change this list without review from a DOM peer!
-    "PropertyNodeList",
-// IMPORTANT: Do not change this list without review from a DOM peer!
     {name: "PushManager", b2g: false, nightlyAndroid: true, android: false},
 // IMPORTANT: Do not change this list without review from a DOM peer!
     {name: "PushSubscription", b2g: false, nightlyAndroid: true, android: false},
 // IMPORTANT: Do not change this list without review from a DOM peer!
     {name: "PushSubscriptionOptions", b2g: false, nightlyAndroid: true, android: false},
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "RadioNodeList",
 // IMPORTANT: Do not change this list without review from a DOM peer!

--- a/dom/webidl/Document.webidl
+++ b/dom/webidl/Document.webidl
@@ -111,17 +111,16 @@ partial interface Document {
   //(HTML only)readonly attribute HTMLHeadElement? head;
   //(HTML only)readonly attribute HTMLCollection images;
   //(HTML only)readonly attribute HTMLCollection embeds;
   //(HTML only)readonly attribute HTMLCollection plugins;
   //(HTML only)readonly attribute HTMLCollection links;
   //(HTML only)readonly attribute HTMLCollection forms;
   //(HTML only)readonly attribute HTMLCollection scripts;
   //(HTML only)NodeList getElementsByName(DOMString elementName);
-  //(HTML only)NodeList getItems(optional DOMString typeNames); // microdata
   //(Not implemented)readonly attribute DOMElementMap cssElementMap;
 
   // dynamic markup insertion
   //(HTML only)Document open(optional DOMString type, optional DOMString replace);
   //(HTML only)WindowProxy open(DOMString url, DOMString name, DOMString features, optional boolean replace);
   //(HTML only)void close();
   //(HTML only)void write(DOMString... text);
   //(HTML only)void writeln(DOMString... text);

--- a/dom/webidl/HTMLDocument.webidl
+++ b/dom/webidl/HTMLDocument.webidl
@@ -25,17 +25,16 @@ interface HTMLDocument : Document {
   readonly attribute HTMLCollection plugins;
   [Pure]
   readonly attribute HTMLCollection links;
   [Pure]
   readonly attribute HTMLCollection forms;
   [Pure]
   readonly attribute HTMLCollection scripts;
   NodeList getElementsByName(DOMString elementName);
-  NodeList getItems(optional DOMString typeNames = ""); // microdata
 
   // dynamic markup insertion
   [Throws]
   Document open(optional DOMString type = "text/html", optional DOMString replace = "");
   [Throws]
   WindowProxy? open(DOMString url, DOMString name, DOMString features, optional boolean replace = false);
   [Throws]
   void close();

--- a/dom/webidl/HTMLElement.webidl
+++ b/dom/webidl/HTMLElement.webidl
@@ -20,29 +20,16 @@ interface HTMLElement : Element {
   [SetterThrows, Pure]
            attribute DOMString dir;
   [Constant]
   readonly attribute DOMStringMap dataset;
 
   [GetterThrows, Pure]
            attribute DOMString innerText;
 
-  // microdata 
-  [SetterThrows, Pure]
-           attribute boolean itemScope;
-  [PutForwards=value,Constant] readonly attribute DOMTokenList itemType;
-  [SetterThrows, Pure]
-           attribute DOMString itemId;
-  [PutForwards=value,Constant] readonly attribute DOMTokenList itemRef;
-  [PutForwards=value,Constant] readonly attribute DOMTokenList itemProp;
-  [Constant]
-  readonly attribute HTMLPropertiesCollection properties;
-  [Throws]
-           attribute any itemValue;
-
   // user interaction
   [SetterThrows, Pure]
            attribute boolean hidden;
   void click();
   [SetterThrows, Pure]
            attribute long tabIndex;
   [Throws]
   void focus();

deleted file mode 100644
--- a/dom/webidl/HTMLPropertiesCollection.webidl
+++ /dev/null
@@ -1,24 +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
- * http://www.whatwg.org/specs/web-apps/current-work/
- *
- * Copyright © 2012 W3C® (MIT, ERCIM, Keio), All Rights Reserved. W3C
- * liability, trademark and document use rules apply.
- */
-
-interface HTMLPropertiesCollection : HTMLCollection {
-  // inherits length and item()
-  getter PropertyNodeList? namedItem(DOMString name); // overrides inherited namedItem()
-  readonly attribute DOMStringList names;
-};
-
-typedef sequence<any> PropertyValueArray;
-
-interface PropertyNodeList : NodeList {
-  [Throws]
-  PropertyValueArray getValues();
-};

--- a/dom/webidl/moz.build
+++ b/dom/webidl/moz.build
@@ -225,17 +225,16 @@ WEBIDL_FILES = [
     'HTMLOptionElement.webidl',
     'HTMLOptionsCollection.webidl',
     'HTMLOutputElement.webidl',
     'HTMLParagraphElement.webidl',
     'HTMLParamElement.webidl',
     'HTMLPictureElement.webidl',
     'HTMLPreElement.webidl',
     'HTMLProgressElement.webidl',
-    'HTMLPropertiesCollection.webidl',
     'HTMLQuoteElement.webidl',
     'HTMLScriptElement.webidl',
     'HTMLSelectElement.webidl',
     'HTMLShadowElement.webidl',
     'HTMLSourceElement.webidl',
     'HTMLSpanElement.webidl',
     'HTMLStyleElement.webidl',
     'HTMLTableCaptionElement.webidl',

--- a/testing/web-platform/meta/html/dom/interfaces.html.ini
+++ b/testing/web-platform/meta/html/dom/interfaces.html.ini
@@ -557,62 +557,62 @@
     expected: FAIL
 
   [HTMLElement interface: attribute onsort]
     expected: FAIL
 
   [HTMLElement interface: document.createElement("noscript") must inherit property "translate" with the proper type (2)]
     expected: FAIL
 
-  [HTMLElement interface: document.createElement("noscript") must inherit property "dropzone" with the proper type (20)]
-    expected: FAIL
-
-  [HTMLElement interface: document.createElement("noscript") must inherit property "forceSpellCheck" with the proper type (25)]
-    expected: FAIL
-
-  [HTMLElement interface: document.createElement("noscript") must inherit property "commandType" with the proper type (26)]
-    expected: FAIL
-
-  [HTMLElement interface: document.createElement("noscript") must inherit property "commandLabel" with the proper type (27)]
-    expected: FAIL
-
-  [HTMLElement interface: document.createElement("noscript") must inherit property "commandIcon" with the proper type (28)]
-    expected: FAIL
-
-  [HTMLElement interface: document.createElement("noscript") must inherit property "commandHidden" with the proper type (29)]
-    expected: FAIL
-
-  [HTMLElement interface: document.createElement("noscript") must inherit property "commandDisabled" with the proper type (30)]
-    expected: FAIL
-
-  [HTMLElement interface: document.createElement("noscript") must inherit property "commandChecked" with the proper type (31)]
-    expected: FAIL
-
-  [HTMLElement interface: document.createElement("noscript") must inherit property "onautocomplete" with the proper type (33)]
-    expected: FAIL
-
-  [HTMLElement interface: document.createElement("noscript") must inherit property "onautocompleteerror" with the proper type (34)]
-    expected: FAIL
-
-  [HTMLElement interface: document.createElement("noscript") must inherit property "oncancel" with the proper type (36)]
-    expected: FAIL
-
-  [HTMLElement interface: document.createElement("noscript") must inherit property "onclose" with the proper type (41)]
-    expected: FAIL
-
-  [HTMLElement interface: document.createElement("noscript") must inherit property "oncuechange" with the proper type (43)]
-    expected: FAIL
-
-  [HTMLElement interface: document.createElement("noscript") must inherit property "ondragexit" with the proper type (48)]
-    expected: FAIL
-
-  [HTMLElement interface: document.createElement("noscript") must inherit property "onmousewheel" with the proper type (74)]
-    expected: FAIL
-
-  [HTMLElement interface: document.createElement("noscript") must inherit property "onsort" with the proper type (87)]
+  [HTMLElement interface: document.createElement("noscript") must inherit property "dropzone" with the proper type (13)]
+    expected: FAIL
+
+  [HTMLElement interface: document.createElement("noscript") must inherit property "forceSpellCheck" with the proper type (18)]
+    expected: FAIL
+
+  [HTMLElement interface: document.createElement("noscript") must inherit property "commandType" with the proper type (19)]
+    expected: FAIL
+
+  [HTMLElement interface: document.createElement("noscript") must inherit property "commandLabel" with the proper type (20)]
+    expected: FAIL
+
+  [HTMLElement interface: document.createElement("noscript") must inherit property "commandIcon" with the proper type (21)]
+    expected: FAIL
+
+  [HTMLElement interface: document.createElement("noscript") must inherit property "commandHidden" with the proper type (22)]
+    expected: FAIL
+
+  [HTMLElement interface: document.createElement("noscript") must inherit property "commandDisabled" with the proper type (23)]
+    expected: FAIL
+
+  [HTMLElement interface: document.createElement("noscript") must inherit property "commandChecked" with the proper type (24)]
+    expected: FAIL
+
+  [HTMLElement interface: document.createElement("noscript") must inherit property "onautocomplete" with the proper type (26)]
+    expected: FAIL
+
+  [HTMLElement interface: document.createElement("noscript") must inherit property "onautocompleteerror" with the proper type (27)]
+    expected: FAIL
+
+  [HTMLElement interface: document.createElement("noscript") must inherit property "oncancel" with the proper type (29)]
+    expected: FAIL
+
+  [HTMLElement interface: document.createElement("noscript") must inherit property "onclose" with the proper type (34)]
+    expected: FAIL
+
+  [HTMLElement interface: document.createElement("noscript") must inherit property "oncuechange" with the proper type (36)]
+    expected: FAIL
+
+  [HTMLElement interface: document.createElement("noscript") must inherit property "ondragexit" with the proper type (41)]
+    expected: FAIL
+
+  [HTMLElement interface: document.createElement("noscript") must inherit property "onmousewheel" with the proper type (67)]
+    expected: FAIL
+
+  [HTMLElement interface: document.createElement("noscript") must inherit property "onsort" with the proper type (80)]
     expected: FAIL
 
   [Element interface: document.createElement("noscript") must inherit property "query" with the proper type (33)]
     expected: FAIL
 
   [Element interface: calling query(DOMString) on document.createElement("noscript") with too few arguments must throw TypeError]
     expected: FAIL
 
@@ -2633,161 +2633,155 @@
     expected: FAIL
 
   [Document interface: new Document() must inherit property "getElementsByName" with the proper type (51)]
     expected: FAIL
 
   [Document interface: calling getElementsByName(DOMString) on new Document() with too few arguments must throw TypeError]
     expected: FAIL
 
-  [Document interface: new Document() must inherit property "getItems" with the proper type (52)]
-    expected: FAIL
-
-  [Document interface: calling getItems(DOMString) on new Document() with too few arguments must throw TypeError]
-    expected: FAIL
-
-  [Document interface: new Document() must inherit property "cssElementMap" with the proper type (53)]
-    expected: FAIL
-
-  [Document interface: new Document() must inherit property "open" with the proper type (55)]
+  [Document interface: new Document() must inherit property "cssElementMap" with the proper type (52)]
+    expected: FAIL
+
+  [Document interface: new Document() must inherit property "open" with the proper type (54)]
     expected: FAIL
 
   [Document interface: calling open(DOMString,DOMString) on new Document() with too few arguments must throw TypeError]
     expected: FAIL
 
-  [Document interface: new Document() must inherit property "open" with the proper type (56)]
+  [Document interface: new Document() must inherit property "open" with the proper type (55)]
     expected: FAIL
 
   [Document interface: calling open(DOMString,DOMString,DOMString,boolean) on new Document() with too few arguments must throw TypeError]
     expected: FAIL
 
-  [Document interface: new Document() must inherit property "close" with the proper type (57)]
-    expected: FAIL
-
-  [Document interface: new Document() must inherit property "write" with the proper type (58)]
+  [Document interface: new Document() must inherit property "close" with the proper type (56)]
+    expected: FAIL
+
+  [Document interface: new Document() must inherit property "write" with the proper type (57)]
     expected: FAIL
 
   [Document interface: calling write(DOMString) on new Document() with too few arguments must throw TypeError]
     expected: FAIL
 
-  [Document interface: new Document() must inherit property "writeln" with the proper type (59)]
+  [Document interface: new Document() must inherit property "writeln" with the proper type (58)]
     expected: FAIL
 
   [Document interface: calling writeln(DOMString) on new Document() with too few arguments must throw TypeError]
     expected: FAIL
 
-  [Document interface: new Document() must inherit property "designMode" with the proper type (63)]
-    expected: FAIL
-
-  [Document interface: new Document() must inherit property "execCommand" with the proper type (64)]
+  [Document interface: new Document() must inherit property "designMode" with the proper type (62)]
+    expected: FAIL
+
+  [Document interface: new Document() must inherit property "execCommand" with the proper type (63)]
     expected: FAIL
 
   [Document interface: calling execCommand(DOMString,boolean,DOMString) on new Document() with too few arguments must throw TypeError]
     expected: FAIL
 
-  [Document interface: new Document() must inherit property "queryCommandEnabled" with the proper type (65)]
+  [Document interface: new Document() must inherit property "queryCommandEnabled" with the proper type (64)]
     expected: FAIL
 
   [Document interface: calling queryCommandEnabled(DOMString) on new Document() with too few arguments must throw TypeError]
     expected: FAIL
 
-  [Document interface: new Document() must inherit property "queryCommandIndeterm" with the proper type (66)]
+  [Document interface: new Document() must inherit property "queryCommandIndeterm" with the proper type (65)]
     expected: FAIL
 
   [Document interface: calling queryCommandIndeterm(DOMString) on new Document() with too few arguments must throw TypeError]
     expected: FAIL
 
-  [Document interface: new Document() must inherit property "queryCommandState" with the proper type (67)]
+  [Document interface: new Document() must inherit property "queryCommandState" with the proper type (66)]
     expected: FAIL
 
   [Document interface: calling queryCommandState(DOMString) on new Document() with too few arguments must throw TypeError]
     expected: FAIL
 
-  [Document interface: new Document() must inherit property "queryCommandSupported" with the proper type (68)]
+  [Document interface: new Document() must inherit property "queryCommandSupported" with the proper type (67)]
     expected: FAIL
 
   [Document interface: calling queryCommandSupported(DOMString) on new Document() with too few arguments must throw TypeError]
     expected: FAIL
 
-  [Document interface: new Document() must inherit property "queryCommandValue" with the proper type (69)]
+  [Document interface: new Document() must inherit property "queryCommandValue" with the proper type (68)]
     expected: FAIL
 
   [Document interface: calling queryCommandValue(DOMString) on new Document() with too few arguments must throw TypeError]
     expected: FAIL
 
-  [Document interface: new Document() must inherit property "commands" with the proper type (70)]
-    expected: FAIL
-
-  [Document interface: new Document() must inherit property "fgColor" with the proper type (72)]
-    expected: FAIL
-
-  [Document interface: new Document() must inherit property "linkColor" with the proper type (73)]
-    expected: FAIL
-
-  [Document interface: new Document() must inherit property "vlinkColor" with the proper type (74)]
-    expected: FAIL
-
-  [Document interface: new Document() must inherit property "alinkColor" with the proper type (75)]
-    expected: FAIL
-
-  [Document interface: new Document() must inherit property "bgColor" with the proper type (76)]
-    expected: FAIL
-
-  [Document interface: new Document() must inherit property "anchors" with the proper type (77)]
-    expected: FAIL
-
-  [Document interface: new Document() must inherit property "applets" with the proper type (78)]
-    expected: FAIL
-
-  [Document interface: new Document() must inherit property "clear" with the proper type (79)]
-    expected: FAIL
-
-  [Document interface: new Document() must inherit property "captureEvents" with the proper type (80)]
-    expected: FAIL
-
-  [Document interface: new Document() must inherit property "releaseEvents" with the proper type (81)]
-    expected: FAIL
-
-  [Document interface: new Document() must inherit property "all" with the proper type (82)]
-    expected: FAIL
-
-  [Document interface: new Document() must inherit property "query" with the proper type (90)]
+  [Document interface: new Document() must inherit property "commands" with the proper type (69)]
+    expected: FAIL
+
+  [Document interface: new Document() must inherit property "fgColor" with the proper type (71)]
+    expected: FAIL
+
+  [Document interface: new Document() must inherit property "linkColor" with the proper type (72)]
+    expected: FAIL
+
+  [Document interface: new Document() must inherit property "vlinkColor" with the proper type (73)]
+    expected: FAIL
+
+  [Document interface: new Document() must inherit property "alinkColor" with the proper type (74)]
+    expected: FAIL
+
+  [Document interface: new Document() must inherit property "bgColor" with the proper type (75)]
+    expected: FAIL
+
+  [Document interface: new Document() must inherit property "anchors" with the proper type (76)]
+    expected: FAIL
+
+  [Document interface: new Document() must inherit property "applets" with the proper type (77)]
+    expected: FAIL
+
+  [Document interface: new Document() must inherit property "clear" with the proper type (78)]
+    expected: FAIL
+
+  [Document interface: new Document() must inherit property "captureEvents" with the proper type (79)]
+    expected: FAIL
+
+  [Document interface: new Document() must inherit property "releaseEvents" with the proper type (80)]
+    expected: FAIL
+
+  [Document interface: new Document() must inherit property "all" with the proper type (81)]
+    expected: FAIL
+
+  [Document interface: new Document() must inherit property "query" with the proper type (89)]
     expected: FAIL
 
   [Document interface: calling query(DOMString) on new Document() with too few arguments must throw TypeError]
     expected: FAIL
 
-  [Document interface: new Document() must inherit property "queryAll" with the proper type (91)]
+  [Document interface: new Document() must inherit property "queryAll" with the proper type (90)]
     expected: FAIL
 
   [Document interface: calling queryAll(DOMString) on new Document() with too few arguments must throw TypeError]
     expected: FAIL
 
-  [Document interface: new Document() must inherit property "onautocomplete" with the proper type (95)]
-    expected: FAIL
-
-  [Document interface: new Document() must inherit property "onautocompleteerror" with the proper type (96)]
-    expected: FAIL
-
-  [Document interface: new Document() must inherit property "oncancel" with the proper type (98)]
-    expected: FAIL
-
-  [Document interface: new Document() must inherit property "onclose" with the proper type (103)]
-    expected: FAIL
-
-  [Document interface: new Document() must inherit property "oncuechange" with the proper type (105)]
-    expected: FAIL
-
-  [Document interface: new Document() must inherit property "ondragexit" with the proper type (110)]
-    expected: FAIL
-
-  [Document interface: new Document() must inherit property "onmousewheel" with the proper type (136)]
-    expected: FAIL
-
-  [Document interface: new Document() must inherit property "onsort" with the proper type (149)]
+  [Document interface: new Document() must inherit property "onautocomplete" with the proper type (94)]
+    expected: FAIL
+
+  [Document interface: new Document() must inherit property "onautocompleteerror" with the proper type (95)]
+    expected: FAIL
+
+  [Document interface: new Document() must inherit property "oncancel" with the proper type (97)]
+    expected: FAIL
+
+  [Document interface: new Document() must inherit property "onclose" with the proper type (102)]
+    expected: FAIL
+
+  [Document interface: new Document() must inherit property "oncuechange" with the proper type (104)]
+    expected: FAIL
+
+  [Document interface: new Document() must inherit property "ondragexit" with the proper type (109)]
+    expected: FAIL
+
+  [Document interface: new Document() must inherit property "onmousewheel" with the proper type (135)]
+    expected: FAIL
+
+  [Document interface: new Document() must inherit property "onsort" with the proper type (148)]
     expected: FAIL
 
   [HTMLSlotElement interface: existence and properties of interface object]
     expected: FAIL
 
   [HTMLSlotElement interface object length]
     expected: FAIL
 

--- a/testing/web-platform/meta/html/infrastructure/urls/resolving-urls/query-encoding/utf-16be.html.ini
+++ b/testing/web-platform/meta/html/infrastructure/urls/resolving-urls/query-encoding/utf-16be.html.ini
@@ -1,15 +1,13 @@
 [utf-16be.html]
   type: testharness
   expected: TIMEOUT
   disabled:
     if os == "mac": https://bugzilla.mozilla.org/show_bug.cgi?id=1034063
-  [Getting <div>.itemid]
-    expected: FAIL
 
   [hyperlink auditing <a ping>]
     expected: TIMEOUT
 
   [hyperlink auditing <area ping>]
     expected: TIMEOUT
 
   [loading image <video poster>]

--- a/testing/web-platform/meta/html/infrastructure/urls/resolving-urls/query-encoding/utf-16le.html.ini
+++ b/testing/web-platform/meta/html/infrastructure/urls/resolving-urls/query-encoding/utf-16le.html.ini
@@ -1,15 +1,13 @@
 [utf-16le.html]
   type: testharness
   disabled:
     if os == "mac": https://bugzilla.mozilla.org/show_bug.cgi?id=1034063
   expected: TIMEOUT
-  [Getting <div>.itemid]
-    expected: FAIL
 
   [hyperlink auditing <a ping>]
     expected: TIMEOUT
 
   [hyperlink auditing <area ping>]
     expected: TIMEOUT
 
   [loading image <video poster>]

--- a/testing/web-platform/meta/html/infrastructure/urls/resolving-urls/query-encoding/utf-8.html.ini
+++ b/testing/web-platform/meta/html/infrastructure/urls/resolving-urls/query-encoding/utf-8.html.ini
@@ -1,15 +1,13 @@
 [utf-8.html]
   type: testharness
   expected: TIMEOUT
   disabled:
     if os == "mac": https://bugzilla.mozilla.org/show_bug.cgi?id=1034063
-  [Getting <div>.itemid]
-    expected: FAIL
 
   [hyperlink auditing <a ping>]
     expected: TIMEOUT
 
   [hyperlink auditing <area ping>]
     expected: TIMEOUT
 
   [loading image <video poster>]

--- a/testing/web-platform/meta/html/infrastructure/urls/resolving-urls/query-encoding/windows-1251.html.ini
+++ b/testing/web-platform/meta/html/infrastructure/urls/resolving-urls/query-encoding/windows-1251.html.ini
@@ -70,19 +70,16 @@
     expected: FAIL
 
   [Getting <menuitem>.icon]
     expected: FAIL
 
   [Getting <script>.src]
     expected: FAIL
 
-  [Getting <div>.itemid]
-    expected: FAIL
-
   [Getting <a>.ping (multiple URLs)]
     expected: FAIL
 
   [follow hyperlink <a href>]
     expected: FAIL
 
   [follow hyperlink <area href>]
     expected: FAIL
@@ -247,49 +244,16 @@
     expected: FAIL
 
   [submit form <button formaction>]
     expected: FAIL
 
   [<base href>]
     expected: FAIL
 
-  [microdata values <audio src>]
-    expected: FAIL
-
-  [microdata values <embed src>]
-    expected: FAIL
-
-  [microdata values <iframe src>]
-    expected: FAIL
-
-  [microdata values <img src>]
-    expected: FAIL
-
-  [microdata values <source src>]
-    expected: FAIL
-
-  [microdata values <track src>]
-    expected: FAIL
-
-  [microdata values <video src>]
-    expected: FAIL
-
-  [microdata values <a href>]
-    expected: FAIL
-
-  [microdata values <area href>]
-    expected: FAIL
-
-  [microdata values <link href>]
-    expected: FAIL
-
-  [microdata values <object data>]
-    expected: FAIL
-
   [Worker constructor]
     expected: FAIL
 
   [SharedWorker constructor]
     expected: FAIL
 
   [EventSource constructor]
     expected: FAIL

--- a/testing/web-platform/meta/html/infrastructure/urls/resolving-urls/query-encoding/windows-1252.html.ini
+++ b/testing/web-platform/meta/html/infrastructure/urls/resolving-urls/query-encoding/windows-1252.html.ini
@@ -1,15 +1,13 @@
 [windows-1252.html]
   type: testharness
   expected: TIMEOUT
   disabled:
     if os == "mac": https://bugzilla.mozilla.org/show_bug.cgi?id=1034063
-  [Getting <div>.itemid]
-    expected: FAIL
 
   [hyperlink auditing <a ping>]
     expected: TIMEOUT
 
   [hyperlink auditing <area ping>]
     expected: TIMEOUT
 
   [loading webvtt <track>]

deleted file mode 100644
--- a/testing/web-platform/tests/html/dom/elements-microdata.js
+++ /dev/null
@@ -1,35 +0,0 @@
-// Up-to-date as of 2013-04-19.
-// Things defined in the W3C's microdata draft, not the main HTML5 draft.
-// Note: must be included last so that it hits all elements.
-
-for (var element in elements) {
-  elements[element].itemScope = "boolean";
-  elements[element].itemType = "settable tokenlist";
-  elements[element].itemId = "url";
-  elements[element].itemRef = "settable tokenlist";
-  elements[element].itemProp = "settable tokenlist";
-}
-extraTests.push(function() {
-  // itemValue only reflects in certain circumstances.  The syntax for our big
-  // array thing above doesn't currently support one IDL attribute that reflects
-  // different content attributes, so just do this explicitly until that's fixed.
-  var reflectItemValue = function(data, localName, attribute) {
-    var element = document.createElement(localName);
-    element.setAttribute("itemprop", "");
-    ReflectionTests.reflects(data, "itemValue", element, attribute);
-  }
-  reflectItemValue("string", "meta", "content");
-  reflectItemValue("url", "audio", "src");
-  reflectItemValue("url", "embed", "src");
-  reflectItemValue("url", "iframe", "src");
-  reflectItemValue("url", "img", "src");
-  reflectItemValue("url", "source", "src");
-  reflectItemValue("url", "track", "src");
-  reflectItemValue("url", "video", "src");
-  reflectItemValue("url", "a", "href");
-  reflectItemValue("url", "area", "href");
-  reflectItemValue("url", "link", "href");
-  reflectItemValue("url", "object", "data");
-  reflectItemValue("string", "data", "value");
-  //TODO: time is more complex
-});

--- a/testing/web-platform/tests/html/dom/interfaces.html
+++ b/testing/web-platform/tests/html/dom/interfaces.html
@@ -893,28 +893,18 @@ interface HTMLOptionsCollection : HTMLCo
            attribute unsigned long length; // shadows inherited length
   legacycaller HTMLOptionElement? (DOMString name);
   setter creator void (unsigned long index, HTMLOptionElement? option);
   void add((HTMLOptionElement or HTMLOptGroupElement) element, optional (HTMLElement or long)? before = null);
   void remove(long index);
            attribute long selectedIndex;
 };
 
-interface HTMLPropertiesCollection : HTMLCollection {
-  // inherits length and item()
-  getter PropertyNodeList? namedItem(DOMString name); // shadows inherited namedItem()
-  readonly attribute DOMString[] names;
-};
-
 typedef sequence<any> PropertyValueArray;
 
-interface PropertyNodeList : NodeList {
-  PropertyValueArray getValues();
-};
-
 [OverrideBuiltins, Exposed=(Window,Worker)]
 interface DOMStringMap {
   getter DOMString (DOMString name);
   setter creator void (DOMString name, DOMString value);
   deleter void (DOMString name);
 };
 
 interface DOMElementMap {
@@ -947,17 +937,16 @@ partial /*sealed*/ interface Document {
   readonly attribute HTMLHeadElement? head;
   readonly attribute HTMLCollection images;
   readonly attribute HTMLCollection embeds;
   readonly attribute HTMLCollection plugins;
   readonly attribute HTMLCollection links;
   readonly attribute HTMLCollection forms;
   readonly attribute HTMLCollection scripts;
   NodeList getElementsByName(DOMString elementName);
-  NodeList getItems(optional DOMString typeNames = ""); // microdata
   readonly attribute DOMElementMap cssElementMap;
   readonly attribute HTMLScriptElement? currentScript;
 
   // dynamic markup insertion
   Document open(optional DOMString type = "text/html", optional DOMString replace = "");
   WindowProxy open(DOMString url, DOMString name, DOMString features, optional boolean replace = false);
   void close();
   void write(DOMString... text);
@@ -990,25 +979,16 @@ partial interface XMLDocument {
 interface HTMLElement : Element {
   // metadata attributes
            attribute DOMString title;
            attribute DOMString lang;
            attribute boolean translate;
            attribute DOMString dir;
   readonly attribute DOMStringMap dataset;
 
-  // microdata
-           attribute boolean itemScope;
-  [PutForwards=value] readonly attribute DOMTokenList itemType;
-           attribute DOMString itemId;
-  [PutForwards=value] readonly attribute DOMTokenList itemRef;
-  [PutForwards=value] readonly attribute DOMTokenList itemProp;
-  readonly attribute HTMLPropertiesCollection properties;
-           attribute any itemValue; // acts as DOMString on setting
-
   // user interaction
            attribute boolean hidden;
   void click();
            attribute long tabIndex;
   void focus();
   void blur();
            attribute DOMString accessKey;
   readonly attribute DOMString accessKeyLabel;
@@ -3189,18 +3169,16 @@ setup(function() {
 }, {explicit_done:true});
 window.onload = function() {
   idlArray.add_objects({
     NodeList: ['document.getElementsByName("name")'],
     HTMLAllCollection: ['document.all'],
     HTMLFormControlsCollection: ['document.createElement("form").elements'],
     RadioNodeList: [],
     HTMLOptionsCollection: ['document.createElement("select").options'],
-    HTMLPropertiesCollection: ['document.head.properties'],
-    PropertyNodeList: [],
     DOMStringMap: ['document.head.dataset'],
     DOMElementMap: ['document.cssElementMap'],
     Transferable: [],
     Document: ['iframe.contentDocument', 'new Document()'],
     XMLDocument: ['document.implementation.createDocument(null, "", null)'],
     HTMLElement: ['document.createElement("noscript")'], // more tests in html/semantics/interfaces.js
     HTMLUnknownElement: ['document.createElement("bgsound")'], // more tests in html/semantics/interfaces.js
     HTMLHtmlElement: ['document.createElement("html")'],

--- a/testing/web-platform/tests/html/dom/reflection-embedded.html
+++ b/testing/web-platform/tests/html/dom/reflection-embedded.html
@@ -9,10 +9,9 @@ is suitable for incorporation into autom
 
 <div id=log></div>
 
 <script src="/resources/testharness.js"></script>
 <script src=/resources/testharnessreport.js></script>
 <script src=original-harness.js></script>
 <script src=new-harness.js></script>
 <script src=elements-embedded.js></script>
-<script src=elements-microdata.js></script>
 <script src=reflection.js></script>

--- a/testing/web-platform/tests/html/dom/reflection-forms.html
+++ b/testing/web-platform/tests/html/dom/reflection-forms.html
@@ -9,10 +9,9 @@ is suitable for incorporation into autom
 
 <div id=log></div>
 
 <script src="/resources/testharness.js"></script>
 <script src=/resources/testharnessreport.js></script>
 <script src=original-harness.js></script>
 <script src=new-harness.js></script>
 <script src=elements-forms.js></script>
-<script src=elements-microdata.js></script>
 <script src=reflection.js></script>

--- a/testing/web-platform/tests/html/dom/reflection-grouping.html
+++ b/testing/web-platform/tests/html/dom/reflection-grouping.html
@@ -9,10 +9,9 @@ is suitable for incorporation into autom
 
 <div id=log></div>
 
 <script src="/resources/testharness.js"></script>
 <script src=/resources/testharnessreport.js></script>
 <script src=original-harness.js></script>
 <script src=new-harness.js></script>
 <script src=elements-grouping.js></script>
-<script src=elements-microdata.js></script>
 <script src=reflection.js></script>

--- a/testing/web-platform/tests/html/dom/reflection-metadata.html
+++ b/testing/web-platform/tests/html/dom/reflection-metadata.html
@@ -9,10 +9,9 @@ is suitable for incorporation into autom
 
 <div id=log></div>
 
 <script src="/resources/testharness.js"></script>
 <script src=/resources/testharnessreport.js></script>
 <script src=original-harness.js></script>
 <script src=new-harness.js></script>
 <script src=elements-metadata.js></script>
-<script src=elements-microdata.js></script>
 <script src=reflection.js></script>

--- a/testing/web-platform/tests/html/dom/reflection-misc.html
+++ b/testing/web-platform/tests/html/dom/reflection-misc.html
@@ -9,10 +9,9 @@ is suitable for incorporation into autom
 
 <div id=log></div>
 
 <script src="/resources/testharness.js"></script>
 <script src=/resources/testharnessreport.js></script>
 <script src=original-harness.js></script>
 <script src=new-harness.js></script>
 <script src=elements-misc.js></script>
-<script src=elements-microdata.js></script>
 <script src=reflection.js></script>

--- a/testing/web-platform/tests/html/dom/reflection-obsolete.html
+++ b/testing/web-platform/tests/html/dom/reflection-obsolete.html
@@ -9,10 +9,9 @@ is suitable for incorporation into autom
 
 <div id=log></div>
 
 <script src="/resources/testharness.js"></script>
 <script src=/resources/testharnessreport.js></script>
 <script src=original-harness.js></script>
 <script src=new-harness.js></script>
 <script src=elements-obsolete.js></script>
-<script src=elements-microdata.js></script>
 <script src=reflection.js></script>

--- a/testing/web-platform/tests/html/dom/reflection-original.html
+++ b/testing/web-platform/tests/html/dom/reflection-original.html
@@ -32,10 +32,9 @@ frameworks.
 <script src=elements-sections.js></script>
 <script src=elements-grouping.js></script>
 <script src=elements-text.js></script>
 <script src=elements-embedded.js></script>
 <script src=elements-tabular.js></script>
 <script src=elements-forms.js></script>
 <script src=elements-misc.js></script>
 <script src=elements-obsolete.js></script>
-<script src=elements-microdata.js></script>
 <script src=reflection.js></script>

--- a/testing/web-platform/tests/html/dom/reflection-sections.html
+++ b/testing/web-platform/tests/html/dom/reflection-sections.html
@@ -9,10 +9,9 @@ is suitable for incorporation into autom
 
 <div id=log></div>
 
 <script src="/resources/testharness.js"></script>
 <script src=/resources/testharnessreport.js></script>
 <script src=original-harness.js></script>
 <script src=new-harness.js></script>
 <script src=elements-sections.js></script>
-<script src=elements-microdata.js></script>
 <script src=reflection.js></script>

--- a/testing/web-platform/tests/html/dom/reflection-tabular.html
+++ b/testing/web-platform/tests/html/dom/reflection-tabular.html
@@ -9,10 +9,9 @@ is suitable for incorporation into autom
 
 <div id=log></div>
 
 <script src="/resources/testharness.js"></script>
 <script src=/resources/testharnessreport.js></script>
 <script src=original-harness.js></script>
 <script src=new-harness.js></script>
 <script src=elements-tabular.js></script>
-<script src=elements-microdata.js></script>
 <script src=reflection.js></script>

--- a/testing/web-platform/tests/html/dom/reflection-text.html
+++ b/testing/web-platform/tests/html/dom/reflection-text.html
@@ -9,10 +9,9 @@ is suitable for incorporation into autom
 
 <div id=log></div>
 
 <script src="/resources/testharness.js"></script>
 <script src=/resources/testharnessreport.js></script>
 <script src=original-harness.js></script>
 <script src=new-harness.js></script>
 <script src=elements-text.js></script>
-<script src=elements-microdata.js></script>
 <script src=reflection.js></script>

--- a/testing/web-platform/tests/html/infrastructure/urls/resolving-urls/query-encoding/resources/resolve-url.js
+++ b/testing/web-platform/tests/html/infrastructure/urls/resolving-urls/query-encoding/resources/resolve-url.js
@@ -80,17 +80,17 @@ onload = function() {
       elm.setAttribute(attr, input);
       var got = elm[idlAttr];
       assert_true(got.indexOf(expected_current) > -1, msg(expected_current, got));
     }, 'Getting <'+tag+'>.'+idlAttr + (multiple ? ' (multiple URLs)' : ''),
     {help:'https://html.spec.whatwg.org/multipage/multipage/common-dom-interfaces.html#reflecting-content-attributes-in-idl-attributes'});
   }
 
   ('iframe src, a href, base href, link href, img src, embed src, object data, track src, video src, audio src, input src, form action, ' +
-  'input formaction formAction, button formaction formAction, menuitem icon, script src, div itemid').split(', ').forEach(function(str) {
+  'input formaction formAction, button formaction formAction, menuitem icon, script src').split(', ').forEach(function(str) {
     var arr = str.split(' ');
     test_reflecting(arr[0], arr[1], arr[2]);
   });
 
   'a ping'.split(', ').forEach(function(str) {
     var arr = str.split(' ');
     test_reflecting(arr[0], arr[1], arr[2], true);
   });
@@ -430,36 +430,16 @@ onload = function() {
       var got_a_href = doc.links[0].href;
       assert_true(got_a_href.indexOf(expected_current) > -1, msg(expected_current, got_a_href), 'a.href');
     });
   }, '<base href>',
   {help:['https://html.spec.whatwg.org/multipage/multipage/semantics.html#set-the-frozen-base-url',
   'https://dom.spec.whatwg.org/#dom-node-baseuri',
   'https://html.spec.whatwg.org/multipage/multipage/text-level-semantics.html#the-a-element']});
 
-  // XXX itemid is exposed in JSON drag-and-drop but seems hard to automate
-
-  // microdata values
-  function test_microdata_values(tag, attr) {
-    test(function() {
-      var elm = document.createElement(tag);
-      elm.setAttribute('itemprop', '');
-      elm.setAttribute(attr, input_url_html);
-      var got = elm.itemValue;
-      assert_not_equals(got, undefined, 'itemValue not supported');
-      assert_true(got.indexOf(expected_current) > -1, msg(expected_current, got));
-    }, 'microdata values <'+tag+' '+attr+'>',
-    {help:'https://html.spec.whatwg.org/multipage/multipage/microdata.html#concept-property-value'});
-  }
-
-  'audio src, embed src, iframe src, img src, source src, track src, video src, a href, area href, link href, object data'.split(', ').forEach(function(str) {
-    var arr = str.split(' ');
-    test_microdata_values(arr[0], arr[1]);
-  });
-
   // XXX drag and drop (<a href> or <img src>) seems hard to automate
 
   // Worker()
   async_test(function() {
     var worker = new Worker(input_url_worker);
     worker.onmessage = this.step_func_done(function(e) {
       assert_equals(e.data, expected_current);
     });

--- a/testing/web-platform/tests/tools/scripts/id2path.json
+++ b/testing/web-platform/tests/tools/scripts/id2path.json
@@ -810,13 +810,11 @@
     "using-the-microdata-dom-api": "microdata/introduction/using-the-microdata-dom-api",
     "encoding-microdata": "microdata/encoding-microdata",
     "the-microdata-model": "microdata/encoding-microdata/the-microdata-model",
     "items": "microdata/encoding-microdata/items",
     "names:-the-itemprop-attribute": "microdata/encoding-microdata/names-the-itemprop-attribute",
     "values": "microdata/encoding-microdata/values",
     "associating-names-with-items": "microdata/encoding-microdata/associating-names-with-items",
     "microdata-and-other-namespaces": "microdata/encoding-microdata/microdata-and-other-namespaces",
-    "microdata-dom-api": "microdata/microdata-dom-api",
-    "htmlpropertiescollection": "microdata/microdata-dom-api/htmlpropertiescollection",
     "converting-html-to-other-formats": "microdata/converting-html-to-other-formats",
     "json": "microdata/converting-html-to-other-formats/json"
-}
\ No newline at end of file
+}