--- a/accessible/atk/UtilInterface.cpp
+++ b/accessible/atk/UtilInterface.cpp
@@ -260,17 +260,18 @@ mai_util_add_key_event_listener(AtkKeySn
   static guint key = 0;
 
   if (!sKey_listener_list) {
     sKey_listener_list = g_hash_table_new(nullptr, nullptr);
     sKey_snooper_id = gtk_key_snooper_install(mai_key_snooper, data);
   }
   AtkKeySnoopFuncPointer atkKeySnoop;
   atkKeySnoop.func_ptr = listener;
-  g_hash_table_insert(sKey_listener_list, GUINT_TO_POINTER(key++),
+  key++;
+  g_hash_table_insert(sKey_listener_list, GUINT_TO_POINTER(key),
                       atkKeySnoop.data);
   return key;
 }
 
 static void
 mai_util_remove_key_event_listener (guint remove_listener)
 {
     if (!sKey_listener_list) {

--- a/chrome/nsChromeRegistry.cpp
+++ b/chrome/nsChromeRegistry.cpp
@@ -24,24 +24,24 @@
 #include "nsIDOMLocation.h"
 #include "nsIDOMWindowCollection.h"
 #include "nsIDOMWindow.h"
 #include "nsIObserverService.h"
 #include "nsIPresShell.h"
 #include "nsIScriptError.h"
 #include "nsIWindowMediator.h"
 #include "nsIPrefService.h"
-#include "mozilla/StyleSheetHandle.h"
-#include "mozilla/StyleSheetHandleInlines.h"
+#include "mozilla/StyleSheet.h"
+#include "mozilla/StyleSheetInlines.h"
 
 nsChromeRegistry* nsChromeRegistry::gChromeRegistry;
 
 // DO NOT use namespace mozilla; it'll break due to a naming conflict between
 // mozilla::TextRange and a TextRange in OSX headers.
-using mozilla::StyleSheetHandle;
+using mozilla::StyleSheet;
 using mozilla::dom::IsChromeURI;
 
 ////////////////////////////////////////////////////////////////////////////////
 
 void
 nsChromeRegistry::LogMessage(const char* aMsg, ...)
 {
   nsCOMPtr<nsIConsoleService> console 
@@ -397,27 +397,27 @@ nsresult nsChromeRegistry::RefreshWindow
   nsCOMPtr<nsIDocument> document = aWindow->GetDoc();
   if (!document)
     return NS_OK;
 
   // Deal with the agent sheets first.  Have to do all the style sets by hand.
   nsCOMPtr<nsIPresShell> shell = document->GetShell();
   if (shell) {
     // Reload only the chrome URL agent style sheets.
-    nsTArray<StyleSheetHandle::RefPtr> agentSheets;
+    nsTArray<RefPtr<StyleSheet>> agentSheets;
     rv = shell->GetAgentStyleSheets(agentSheets);
     NS_ENSURE_SUCCESS(rv, rv);
 
-    nsTArray<StyleSheetHandle::RefPtr> newAgentSheets;
-    for (StyleSheetHandle sheet : agentSheets) {
+    nsTArray<RefPtr<StyleSheet>> newAgentSheets;
+    for (StyleSheet* sheet : agentSheets) {
       nsIURI* uri = sheet->GetSheetURI();
 
       if (IsChromeURI(uri)) {
         // Reload the sheet.
-        StyleSheetHandle::RefPtr newSheet;
+        RefPtr<StyleSheet> newSheet;
         rv = document->LoadChromeSheetSync(uri, true, &newSheet);
         if (NS_FAILED(rv)) return rv;
         if (newSheet) {
           rv = newAgentSheets.AppendElement(newSheet) ? NS_OK : NS_ERROR_FAILURE;
           if (NS_FAILED(rv)) return rv;
         }
       }
       else {  // Just use the same sheet.
@@ -428,36 +428,36 @@ nsresult nsChromeRegistry::RefreshWindow
 
     rv = shell->SetAgentStyleSheets(newAgentSheets);
     NS_ENSURE_SUCCESS(rv, rv);
   }
 
   int32_t count = document->GetNumberOfStyleSheets();
 
   // Build an array of style sheets we need to reload.
-  nsTArray<StyleSheetHandle::RefPtr> oldSheets(count);
-  nsTArray<StyleSheetHandle::RefPtr> newSheets(count);
+  nsTArray<RefPtr<StyleSheet>> oldSheets(count);
+  nsTArray<RefPtr<StyleSheet>> newSheets(count);
 
   // Iterate over the style sheets.
   for (int32_t i = 0; i < count; i++) {
     // Get the style sheet
-    StyleSheetHandle styleSheet = document->GetStyleSheetAt(i);
+    StyleSheet* styleSheet = document->GetStyleSheetAt(i);
     oldSheets.AppendElement(styleSheet);
   }
 
   // Iterate over our old sheets and kick off a sync load of the new
   // sheet if and only if it's a non-inline sheet with a chrome URL.
-  for (StyleSheetHandle sheet : oldSheets) {
+  for (StyleSheet* sheet : oldSheets) {
     MOZ_ASSERT(sheet, "GetStyleSheetAt shouldn't return nullptr for "
                       "in-range sheet indexes");
     nsIURI* uri = sheet->GetSheetURI();
 
     if (!sheet->IsInline() && IsChromeURI(uri)) {
       // Reload the sheet.
-      StyleSheetHandle::RefPtr newSheet;
+      RefPtr<StyleSheet> newSheet;
       // XXX what about chrome sheets that have a title or are disabled?  This
       // only works by sheer dumb luck.
       document->LoadChromeSheetSync(uri, false, &newSheet);
       // Even if it's null, we put in in there.
       newSheets.AppendElement(newSheet);
     } else {
       // Just use the same sheet.
       newSheets.AppendElement(sheet);

--- a/config/external/nss/nss.symbols
+++ b/config/external/nss/nss.symbols
@@ -668,23 +668,25 @@ SSL_GetClientAuthDataHook
 SSL_GetImplementedCiphers
 SSL_GetNextProto
 SSL_GetNumImplementedCiphers
 SSL_GetSRTPCipher
 SSL_HandshakeCallback
 SSL_HandshakeNegotiatedExtension
 SSL_ImplementedCiphers @DATA@
 SSL_ImportFD
+SSL_NamedGroupConfig
 SSL_NumImplementedCiphers @DATA@
 SSL_OptionSet
 SSL_OptionSetDefault
 SSL_PeerCertificate
 SSL_PeerCertificateChain
 SSL_PeerStapledOCSPResponses
 SSL_ResetHandshake
+SSL_SendAdditionalKeyShares
 SSL_SetCanFalseStartCallback
 SSL_SetDowngradeCheckVersion
 SSL_SetNextProtoNego
 SSL_SetPKCS11PinArg
 SSL_SetSockPeerID
 SSL_SetSRTPCiphers
 SSL_SetStapledOCSPResponses
 SSL_SetURL

--- a/dom/base/ShadowRoot.cpp
+++ b/dom/base/ShadowRoot.cpp
@@ -12,18 +12,18 @@
 #include "nsContentUtils.h"
 #include "nsDOMClassInfoID.h"
 #include "nsIDOMHTMLElement.h"
 #include "nsIStyleSheetLinkingElement.h"
 #include "mozilla/dom/Element.h"
 #include "mozilla/dom/HTMLContentElement.h"
 #include "mozilla/dom/HTMLShadowElement.h"
 #include "nsXBLPrototypeBinding.h"
-#include "mozilla/StyleSheetHandle.h"
-#include "mozilla/StyleSheetHandleInlines.h"
+#include "mozilla/StyleSheet.h"
+#include "mozilla/StyleSheetInlines.h"
 
 using namespace mozilla;
 using namespace mozilla::dom;
 
 NS_IMPL_CYCLE_COLLECTION_CLASS(ShadowRoot)
 
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(ShadowRoot,
                                                   DocumentFragment)
@@ -127,17 +127,17 @@ ShadowRoot::StyleSheetChanged()
   if (shell) {
     OwnerDoc()->BeginUpdate(UPDATE_STYLE);
     shell->RecordShadowStyleChange(this);
     OwnerDoc()->EndUpdate(UPDATE_STYLE);
   }
 }
 
 void
-ShadowRoot::InsertSheet(StyleSheetHandle aSheet,
+ShadowRoot::InsertSheet(StyleSheet* aSheet,
                         nsIContent* aLinkingContent)
 {
   nsCOMPtr<nsIStyleSheetLinkingElement>
     linkingElement = do_QueryInterface(aLinkingContent);
   MOZ_ASSERT(linkingElement, "The only styles in a ShadowRoot should come "
                              "from <style>.");
 
   linkingElement->SetStyleSheet(aSheet); // This sets the ownerNode on the sheet
@@ -158,17 +158,17 @@ ShadowRoot::InsertSheet(StyleSheetHandle
   }
 
   if (aSheet->IsApplicable()) {
     StyleSheetChanged();
   }
 }
 
 void
-ShadowRoot::RemoveSheet(StyleSheetHandle aSheet)
+ShadowRoot::RemoveSheet(StyleSheet* aSheet)
 {
   mProtoBinding->RemoveStyleSheet(aSheet);
 
   if (aSheet->IsApplicable()) {
     StyleSheetChanged();
   }
 }
 
@@ -751,17 +751,17 @@ ShadowRootStyleSheetList::IndexedGetter(
   aFound = aIndex < mShadowRoot->mProtoBinding->SheetCount();
 
   if (!aFound) {
     return nullptr;
   }
 
   // XXXheycam Return null until ServoStyleSheet implements the right
   // DOM interfaces.
-  StyleSheetHandle sheet = mShadowRoot->mProtoBinding->StyleSheetAt(aIndex);
+  StyleSheet* sheet = mShadowRoot->mProtoBinding->StyleSheetAt(aIndex);
   if (sheet->IsServo()) {
     NS_ERROR("stylo: can't return ServoStyleSheets to script yet");
     return nullptr;
   }
   return sheet->AsGecko();
 }
 
 uint32_t

--- a/dom/base/ShadowRoot.h
+++ b/dom/base/ShadowRoot.h
@@ -4,17 +4,17 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #ifndef mozilla_dom_shadowroot_h__
 #define mozilla_dom_shadowroot_h__
 
 #include "mozilla/dom/DocumentFragment.h"
 #include "mozilla/dom/StyleSheetList.h"
-#include "mozilla/StyleSheetHandle.h"
+#include "mozilla/StyleSheet.h"
 #include "nsCOMPtr.h"
 #include "nsCycleCollectionParticipant.h"
 #include "nsIContentInlines.h"
 #include "nsTHashtable.h"
 #include "nsDocument.h"
 
 class nsIAtom;
 class nsIContent;
@@ -42,18 +42,18 @@ public:
   NS_DECL_NSIMUTATIONOBSERVER_CONTENTINSERTED
   NS_DECL_NSIMUTATIONOBSERVER_CONTENTREMOVED
 
   ShadowRoot(nsIContent* aContent, already_AddRefed<mozilla::dom::NodeInfo>&& aNodeInfo,
              nsXBLPrototypeBinding* aProtoBinding);
 
   void AddToIdTable(Element* aElement, nsIAtom* aId);
   void RemoveFromIdTable(Element* aElement, nsIAtom* aId);
-  void InsertSheet(StyleSheetHandle aSheet, nsIContent* aLinkingContent);
-  void RemoveSheet(StyleSheetHandle aSheet);
+  void InsertSheet(StyleSheet* aSheet, nsIContent* aLinkingContent);
+  void RemoveSheet(StyleSheet* aSheet);
   bool ApplyAuthorStyles();
   void SetApplyAuthorStyles(bool aApplyAuthorStyles);
   StyleSheetList* StyleSheets();
   HTMLShadowElement* GetShadowElement() { return mShadowElement; }
 
   /**
    * Sets the current shadow insertion point where the older
    * ShadowRoot will be projected.

--- a/dom/base/nsContentSink.cpp
+++ b/dom/base/nsContentSink.cpp
@@ -202,17 +202,17 @@ nsContentSink::Init(nsIDocument* aDoc,
     mDynamicLowerValue = sEnablePerfMode == 1;
     FavorPerformanceHint(!mDynamicLowerValue, 0);
   }
 
   return NS_OK;
 }
 
 NS_IMETHODIMP
-nsContentSink::StyleSheetLoaded(StyleSheetHandle aSheet,
+nsContentSink::StyleSheetLoaded(StyleSheet* aSheet,
                                 bool aWasAlternate,
                                 nsresult aStatus)
 {
   NS_ASSERTION(!mRunsToCompletion, "How come a fragment parser observed sheets?");
   if (!aWasAlternate) {
     NS_ASSERTION(mPendingSheetCount > 0, "How'd that happen?");
     --mPendingSheetCount;
 

--- a/dom/base/nsContentSink.h
+++ b/dom/base/nsContentSink.h
@@ -80,17 +80,17 @@ class nsContentSink : public nsICSSLoade
 {
   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
   NS_DECL_CYCLE_COLLECTION_CLASS_AMBIGUOUS(nsContentSink,
                                            nsICSSLoaderObserver)
     // nsITimerCallback
   NS_DECL_NSITIMERCALLBACK
 
   // nsICSSLoaderObserver
-  NS_IMETHOD StyleSheetLoaded(mozilla::StyleSheetHandle aSheet,
+  NS_IMETHOD StyleSheetLoaded(mozilla::StyleSheet* aSheet,
                               bool aWasAlternate,
                               nsresult aStatus) override;
 
   virtual nsresult ProcessMETATag(nsIContent* aContent);
 
   // nsIContentSink implementation helpers
   nsresult WillParseImpl(void);
   nsresult WillInterruptImpl(void);

--- a/dom/base/nsDOMWindowUtils.cpp
+++ b/dom/base/nsDOMWindowUtils.cpp
@@ -104,17 +104,17 @@
 #include "nsContentPermissionHelper.h"
 #include "nsCSSPseudoElements.h"            // for CSSPseudoElementType
 #include "nsNetUtil.h"
 #include "nsDocument.h"
 #include "HTMLImageElement.h"
 #include "mozilla/css/ImageLoader.h"
 #include "mozilla/layers/APZCTreeManager.h" // for layers::ZoomToRectBehavior
 #include "mozilla/dom/Promise.h"
-#include "mozilla/CSSStyleSheet.h"
+#include "mozilla/StyleSheetInlines.h"
 
 #ifdef XP_WIN
 #undef GetClassName
 #endif
 
 using namespace mozilla;
 using namespace mozilla::dom;
 using namespace mozilla::ipc;

--- a/dom/base/nsDocument.cpp
+++ b/dom/base/nsDocument.cpp
@@ -245,18 +245,18 @@
 #include "nsWindowMemoryReporter.h"
 #include "mozilla/dom/Location.h"
 #include "mozilla/dom/FontFaceSet.h"
 #include "mozilla/dom/BoxObject.h"
 #include "gfxPrefs.h"
 #include "nsISupportsPrimitives.h"
 #include "mozilla/StyleSetHandle.h"
 #include "mozilla/StyleSetHandleInlines.h"
-#include "mozilla/StyleSheetHandle.h"
-#include "mozilla/StyleSheetHandleInlines.h"
+#include "mozilla/StyleSheet.h"
+#include "mozilla/StyleSheetInlines.h"
 
 #include "mozilla/DocLoadingTimelineMarker.h"
 
 #include "nsISpeculativeConnect.h"
 
 #include "mozilla/MediaManager.h"
 #ifdef MOZ_WEBRTC
 #include "IPeerConnection.h"
@@ -595,17 +595,17 @@ CSSStyleSheet*
 nsDOMStyleSheetList::IndexedGetter(uint32_t aIndex, bool& aFound)
 {
   if (!mDocument || aIndex >= (uint32_t)mDocument->GetNumberOfStyleSheets()) {
     aFound = false;
     return nullptr;
   }
 
   aFound = true;
-  StyleSheetHandle sheet = mDocument->GetStyleSheetAt(aIndex);
+  StyleSheet* sheet = mDocument->GetStyleSheetAt(aIndex);
   NS_ASSERTION(sheet, "Must have a sheet");
 
   // XXXheycam Return null until ServoStyleSheet implements the right DOM
   // interfaces.
   if (sheet->IsServo()) {
     NS_ERROR("stylo: can't return a ServoStyleSheet to the DOM yet");
     return nullptr;
   }
@@ -614,26 +614,26 @@ nsDOMStyleSheetList::IndexedGetter(uint3
 
 void
 nsDOMStyleSheetList::NodeWillBeDestroyed(const nsINode *aNode)
 {
   mDocument = nullptr;
 }
 
 void
-nsDOMStyleSheetList::StyleSheetAdded(StyleSheetHandle aStyleSheet,
+nsDOMStyleSheetList::StyleSheetAdded(StyleSheet* aStyleSheet,
                                      bool aDocumentSheet)
 {
   if (aDocumentSheet && -1 != mLength) {
     mLength++;
   }
 }
 
 void
-nsDOMStyleSheetList::StyleSheetRemoved(StyleSheetHandle aStyleSheet,
+nsDOMStyleSheetList::StyleSheetRemoved(StyleSheet* aStyleSheet,
                                        bool aDocumentSheet)
 {
   if (aDocumentSheet && -1 != mLength) {
     mLength--;
   }
 }
 
 // nsOnloadBlocker implementation
@@ -1191,17 +1191,17 @@ nsDOMStyleSheetSetList::EnsureFresh()
   if (!mDocument) {
     return; // Spec says "no exceptions", and we have no style sets if we have
             // no document, for sure
   }
 
   int32_t count = mDocument->GetNumberOfStyleSheets();
   nsAutoString title;
   for (int32_t index = 0; index < count; index++) {
-    StyleSheetHandle sheet = mDocument->GetStyleSheetAt(index);
+    StyleSheet* sheet = mDocument->GetStyleSheetAt(index);
     NS_ASSERTION(sheet, "Null sheet in sheet list!");
     // XXXheycam ServoStyleSheets don't expose their title yet.
     if (sheet->IsServo()) {
       NS_ERROR("stylo: ServoStyleSets don't expose their title yet");
       continue;
     }
     sheet->AsGecko()->GetTitle(title);
     if (!title.IsEmpty() && !mNames.Contains(title) && !Add(title)) {
@@ -1492,17 +1492,17 @@ nsDocument::~nsDocument()
   for (uint32_t indx = mChildren.ChildCount(); indx-- != 0; ) {
     mChildren.ChildAt(indx)->UnbindFromTree();
     mChildren.RemoveChildAt(indx);
   }
   mFirstChild = nullptr;
   mCachedRootElement = nullptr;
 
   // Let the stylesheets know we're going away
-  for (StyleSheetHandle sheet : mStyleSheets) {
+  for (StyleSheet* sheet : mStyleSheets) {
     sheet->SetOwningDocument(nullptr);
   }
   if (mAttrStyleSheet) {
     mAttrStyleSheet->SetOwningDocument(nullptr);
   }
   // We don't own the mOnDemandBuiltInUASheets, so we don't need to reset them.
 
   if (mListenerManager) {
@@ -2148,36 +2148,36 @@ nsDocument::ResetToURI(nsIURI *aURI, nsI
     nsGlobalWindow::Cast(win)->RefreshCompartmentPrincipal();
   }
 }
 
 void
 nsDocument::RemoveDocStyleSheetsFromStyleSets()
 {
   // The stylesheets should forget us
-  for (StyleSheetHandle sheet : Reversed(mStyleSheets)) {
+  for (StyleSheet* sheet : Reversed(mStyleSheets)) {
     sheet->SetOwningDocument(nullptr);
 
     if (sheet->IsApplicable()) {
       nsCOMPtr<nsIPresShell> shell = GetShell();
       if (shell) {
         shell->StyleSet()->RemoveDocStyleSheet(sheet);
       }
     }
     // XXX Tell observers?
   }
 }
 
 void
 nsDocument::RemoveStyleSheetsFromStyleSets(
-    const nsTArray<StyleSheetHandle::RefPtr>& aSheets,
+    const nsTArray<RefPtr<StyleSheet>>& aSheets,
     SheetType aType)
 {
   // The stylesheets should forget us
-  for (StyleSheetHandle sheet : Reversed(aSheets)) {
+  for (StyleSheet* sheet : Reversed(aSheets)) {
     sheet->SetOwningDocument(nullptr);
 
     if (sheet->IsApplicable()) {
       nsCOMPtr<nsIPresShell> shell = GetShell();
       if (shell) {
         shell->StyleSet()->RemoveStyleSheet(aType, sheet);
       }
     }
@@ -2245,50 +2245,50 @@ nsDocument::ResetStylesheetsToURI(nsIURI
   nsCOMPtr<nsIPresShell> shell = GetShell();
   if (shell) {
     FillStyleSet(shell->StyleSet());
   }
 }
 
 static void
 AppendSheetsToStyleSet(StyleSetHandle aStyleSet,
-                       const nsTArray<StyleSheetHandle::RefPtr>& aSheets,
+                       const nsTArray<RefPtr<StyleSheet>>& aSheets,
                        SheetType aType)
 {
-  for (StyleSheetHandle sheet : Reversed(aSheets)) {
+  for (StyleSheet* sheet : Reversed(aSheets)) {
     aStyleSet->AppendStyleSheet(aType, sheet);
   }
 }
 
 
 void
 nsDocument::FillStyleSet(StyleSetHandle aStyleSet)
 {
   NS_PRECONDITION(aStyleSet, "Must have a style set");
   NS_PRECONDITION(aStyleSet->SheetCount(SheetType::Doc) == 0,
                   "Style set already has document sheets?");
 
   MOZ_ASSERT(!mStyleSetFilled);
 
-  for (StyleSheetHandle sheet : Reversed(mStyleSheets)) {
+  for (StyleSheet* sheet : Reversed(mStyleSheets)) {
     if (sheet->IsApplicable()) {
       aStyleSet->AddDocStyleSheet(sheet, this);
     }
   }
 
   if (aStyleSet->IsGecko()) {
     nsStyleSheetService *sheetService = nsStyleSheetService::GetInstance();
     if (sheetService) {
-      for (StyleSheetHandle sheet : *sheetService->AuthorStyleSheets()) {
+      for (StyleSheet* sheet : *sheetService->AuthorStyleSheets()) {
         aStyleSet->AppendStyleSheet(SheetType::Doc, sheet);
       }
     }
 
     // Iterate backwards to maintain order
-    for (StyleSheetHandle sheet : Reversed(mOnDemandBuiltInUASheets)) {
+    for (StyleSheet* sheet : Reversed(mOnDemandBuiltInUASheets)) {
       if (sheet->IsApplicable()) {
         aStyleSet->PrependStyleSheet(SheetType::Agent, sheet);
       }
     }
   } else {
     NS_WARNING("stylo: Not yet checking nsStyleSheetService for Servo-backed "
                "documents. See bug 1290224");
   }
@@ -3934,28 +3934,28 @@ nsDocument::RemoveChildAt(uint32_t aInde
     DestroyElementMaps();
   }
 
   doRemoveChildAt(aIndex, aNotify, oldKid, mChildren);
   mCachedRootElement = nullptr;
 }
 
 void
-nsDocument::EnsureOnDemandBuiltInUASheet(StyleSheetHandle aSheet)
+nsDocument::EnsureOnDemandBuiltInUASheet(StyleSheet* aSheet)
 {
   if (mOnDemandBuiltInUASheets.Contains(aSheet)) {
     return;
   }
   BeginUpdate(UPDATE_STYLE);
   AddOnDemandBuiltInUASheet(aSheet);
   EndUpdate(UPDATE_STYLE);
 }
 
 void
-nsDocument::AddOnDemandBuiltInUASheet(StyleSheetHandle aSheet)
+nsDocument::AddOnDemandBuiltInUASheet(StyleSheet* aSheet)
 {
   MOZ_ASSERT(!mOnDemandBuiltInUASheets.Contains(aSheet));
 
   // Prepend here so that we store the sheets in mOnDemandBuiltInUASheets in
   // the same order that they should end up in the style set.
   mOnDemandBuiltInUASheets.InsertElementAt(0, aSheet);
 
   if (aSheet->IsApplicable()) {
@@ -3974,30 +3974,30 @@ nsDocument::AddOnDemandBuiltInUASheet(St
 }
 
 int32_t
 nsDocument::GetNumberOfStyleSheets() const
 {
   return mStyleSheets.Length();
 }
 
-StyleSheetHandle
+StyleSheet*
 nsDocument::GetStyleSheetAt(int32_t aIndex) const
 {
-  return mStyleSheets.SafeElementAt(aIndex, StyleSheetHandle());
+  return mStyleSheets.SafeElementAt(aIndex, nullptr);
 }
 
 int32_t
-nsDocument::GetIndexOfStyleSheet(const StyleSheetHandle aSheet) const
+nsDocument::GetIndexOfStyleSheet(const StyleSheet* aSheet) const
 {
   return mStyleSheets.IndexOf(aSheet);
 }
 
 void
-nsDocument::AddStyleSheetToStyleSets(StyleSheetHandle aSheet)
+nsDocument::AddStyleSheetToStyleSets(StyleSheet* aSheet)
 {
   nsCOMPtr<nsIPresShell> shell = GetShell();
   if (shell) {
     shell->StyleSet()->AddDocStyleSheet(aSheet, this);
   }
 }
 
 #define DO_STYLESHEET_NOTIFICATION(className, type, memberName, argName)      \
@@ -4018,69 +4018,69 @@ nsDocument::AddStyleSheetToStyleSets(Sty
     event->SetTarget(this);                                                   \
     RefPtr<AsyncEventDispatcher> asyncDispatcher =                          \
       new AsyncEventDispatcher(this, event);                                  \
     asyncDispatcher->mOnlyChromeDispatch = true;                              \
     asyncDispatcher->PostDOMEvent();                                          \
   } while (0);
 
 void
-nsDocument::NotifyStyleSheetAdded(StyleSheetHandle aSheet, bool aDocumentSheet)
+nsDocument::NotifyStyleSheetAdded(StyleSheet* aSheet, bool aDocumentSheet)
 {
   NS_DOCUMENT_NOTIFY_OBSERVERS(StyleSheetAdded, (aSheet, aDocumentSheet));
 
   if (StyleSheetChangeEventsEnabled()) {
     DO_STYLESHEET_NOTIFICATION(StyleSheetChangeEvent,
                                "StyleSheetAdded",
                                mDocumentSheet,
                                aDocumentSheet);
   }
 }
 
 void
-nsDocument::NotifyStyleSheetRemoved(StyleSheetHandle aSheet, bool aDocumentSheet)
+nsDocument::NotifyStyleSheetRemoved(StyleSheet* aSheet, bool aDocumentSheet)
 {
   NS_DOCUMENT_NOTIFY_OBSERVERS(StyleSheetRemoved, (aSheet, aDocumentSheet));
 
   if (StyleSheetChangeEventsEnabled()) {
     DO_STYLESHEET_NOTIFICATION(StyleSheetChangeEvent,
                                "StyleSheetRemoved",
                                mDocumentSheet,
                                aDocumentSheet);
   }
 }
 
 void
-nsDocument::AddStyleSheet(StyleSheetHandle aSheet)
+nsDocument::AddStyleSheet(StyleSheet* aSheet)
 {
   NS_PRECONDITION(aSheet, "null arg");
   mStyleSheets.AppendElement(aSheet);
   aSheet->SetOwningDocument(this);
 
   if (aSheet->IsApplicable()) {
     AddStyleSheetToStyleSets(aSheet);
   }
 
   NotifyStyleSheetAdded(aSheet, true);
 }
 
 void
-nsDocument::RemoveStyleSheetFromStyleSets(StyleSheetHandle aSheet)
+nsDocument::RemoveStyleSheetFromStyleSets(StyleSheet* aSheet)
 {
   nsCOMPtr<nsIPresShell> shell = GetShell();
   if (shell) {
     shell->StyleSet()->RemoveDocStyleSheet(aSheet);
   }
 }
 
 void
-nsDocument::RemoveStyleSheet(StyleSheetHandle aSheet)
+nsDocument::RemoveStyleSheet(StyleSheet* aSheet)
 {
   NS_PRECONDITION(aSheet, "null arg");
-  StyleSheetHandle::RefPtr sheet = aSheet; // hold ref so it won't die too soon
+  RefPtr<StyleSheet> sheet = aSheet; // hold ref so it won't die too soon
 
   if (!mStyleSheets.RemoveElement(aSheet)) {
     NS_ASSERTION(mInUnlinkOrDeletion, "stylesheet not found");
     return;
   }
 
   if (!mIsGoingAway) {
     if (aSheet->IsApplicable()) {
@@ -4089,71 +4089,71 @@ nsDocument::RemoveStyleSheet(StyleSheetH
 
     NotifyStyleSheetRemoved(aSheet, true);
   }
 
   aSheet->SetOwningDocument(nullptr);
 }
 
 void
-nsDocument::UpdateStyleSheets(nsTArray<StyleSheetHandle::RefPtr>& aOldSheets,
-                              nsTArray<StyleSheetHandle::RefPtr>& aNewSheets)
+nsDocument::UpdateStyleSheets(nsTArray<RefPtr<StyleSheet>>& aOldSheets,
+                              nsTArray<RefPtr<StyleSheet>>& aNewSheets)
 {
   BeginUpdate(UPDATE_STYLE);
 
   // XXX Need to set the sheet on the ownernode, if any
   NS_PRECONDITION(aOldSheets.Length() == aNewSheets.Length(),
                   "The lists must be the same length!");
   int32_t count = aOldSheets.Length();
 
-  StyleSheetHandle::RefPtr oldSheet;
+  RefPtr<StyleSheet> oldSheet;
   int32_t i;
   for (i = 0; i < count; ++i) {
     oldSheet = aOldSheets[i];
 
     // First remove the old sheet.
     NS_ASSERTION(oldSheet, "None of the old sheets should be null");
     int32_t oldIndex = mStyleSheets.IndexOf(oldSheet);
     RemoveStyleSheet(oldSheet);  // This does the right notifications
 
     // Now put the new one in its place.  If it's null, just ignore it.
-    StyleSheetHandle newSheet = aNewSheets[i];
+    StyleSheet* newSheet = aNewSheets[i];
     if (newSheet) {
       mStyleSheets.InsertElementAt(oldIndex, newSheet);
       newSheet->SetOwningDocument(this);
       if (newSheet->IsApplicable()) {
         AddStyleSheetToStyleSets(newSheet);
       }
 
       NotifyStyleSheetAdded(newSheet, true);
     }
   }
 
   EndUpdate(UPDATE_STYLE);
 }
 
 void
-nsDocument::InsertStyleSheetAt(StyleSheetHandle aSheet, int32_t aIndex)
+nsDocument::InsertStyleSheetAt(StyleSheet* aSheet, int32_t aIndex)
 {
   NS_PRECONDITION(aSheet, "null ptr");
 
   mStyleSheets.InsertElementAt(aIndex, aSheet);
 
   aSheet->SetOwningDocument(this);
 
   if (aSheet->IsApplicable()) {
     AddStyleSheetToStyleSets(aSheet);
   }
 
   NotifyStyleSheetAdded(aSheet, true);
 }
 
 
 void
-nsDocument::SetStyleSheetApplicableState(StyleSheetHandle aSheet,
+nsDocument::SetStyleSheetApplicableState(StyleSheet* aSheet,
                                          bool aApplicable)
 {
   NS_PRECONDITION(aSheet, "null arg");
 
   // If we're actually in the document style sheet list
   if (mStyleSheets.IndexOf(aSheet) != mStyleSheets.NoIndex) {
     if (aApplicable) {
       AddStyleSheetToStyleSets(aSheet);
@@ -4209,17 +4209,17 @@ ConvertAdditionalSheetType(nsIDocument::
     default:
       MOZ_ASSERT(false, "wrong type");
       // we must return something although this should never happen
       return SheetType::Count;
   }
 }
 
 static int32_t
-FindSheet(const nsTArray<StyleSheetHandle::RefPtr>& aSheets, nsIURI* aSheetURI)
+FindSheet(const nsTArray<RefPtr<StyleSheet>>& aSheets, nsIURI* aSheetURI)
 {
   for (int32_t i = aSheets.Length() - 1; i >= 0; i-- ) {
     bool bEqual;
     nsIURI* uri = aSheets[i]->GetSheetURI();
 
     if (uri && NS_SUCCEEDED(uri->Equals(aSheetURI, &bEqual)) && bEqual)
       return i;
   }
@@ -4253,28 +4253,28 @@ nsDocument::LoadAdditionalStyleSheet(add
     case nsIDocument::eAuthorSheet:
       parsingMode = css::eAuthorSheetFeatures;
       break;
 
     default:
       MOZ_CRASH("impossible value for aType");
   }
 
-  StyleSheetHandle::RefPtr sheet;
+  RefPtr<StyleSheet> sheet;
   nsresult rv = loader->LoadSheetSync(aSheetURI, parsingMode, true, &sheet);
   NS_ENSURE_SUCCESS(rv, rv);
 
   sheet->SetOwningDocument(this);
   MOZ_ASSERT(sheet->IsApplicable());
 
   return AddAdditionalStyleSheet(aType, sheet);
 }
 
 nsresult
-nsDocument::AddAdditionalStyleSheet(additionalSheetType aType, StyleSheetHandle aSheet)
+nsDocument::AddAdditionalStyleSheet(additionalSheetType aType, StyleSheet* aSheet)
 {
   if (mAdditionalSheets[aType].Contains(aSheet))
     return NS_ERROR_INVALID_ARG;
 
   if (!aSheet->IsApplicable())
     return NS_ERROR_INVALID_ARG;
 
   mAdditionalSheets[aType].AppendElement(aSheet);
@@ -4293,21 +4293,21 @@ nsDocument::AddAdditionalStyleSheet(addi
   return NS_OK;
 }
 
 void
 nsDocument::RemoveAdditionalStyleSheet(additionalSheetType aType, nsIURI* aSheetURI)
 {
   MOZ_ASSERT(aSheetURI);
 
-  nsTArray<StyleSheetHandle::RefPtr>& sheets = mAdditionalSheets[aType];
+  nsTArray<RefPtr<StyleSheet>>& sheets = mAdditionalSheets[aType];
 
   int32_t i = FindSheet(mAdditionalSheets[aType], aSheetURI);
   if (i >= 0) {
-    StyleSheetHandle::RefPtr sheetRef = sheets[i];
+    RefPtr<StyleSheet> sheetRef = sheets[i];
     sheets.RemoveElementAt(i);
 
     BeginUpdate(UPDATE_STYLE);
     if (!mIsGoingAway) {
       MOZ_ASSERT(sheetRef->IsApplicable());
       nsCOMPtr<nsIPresShell> shell = GetShell();
       if (shell) {
         SheetType type = ConvertAdditionalSheetType(aType);
@@ -4319,20 +4319,20 @@ nsDocument::RemoveAdditionalStyleSheet(a
     // these additional sheets.
     NotifyStyleSheetRemoved(sheetRef, false);
     EndUpdate(UPDATE_STYLE);
 
     sheetRef->SetOwningDocument(nullptr);
   }
 }
 
-StyleSheetHandle
+StyleSheet*
 nsDocument::GetFirstAdditionalAuthorSheet()
 {
-  return mAdditionalSheets[eAuthorSheet].SafeElementAt(0, StyleSheetHandle());
+  return mAdditionalSheets[eAuthorSheet].SafeElementAt(0);
 }
 
 nsIGlobalObject*
 nsDocument::GetScopeObject() const
 {
   nsCOMPtr<nsIGlobalObject> scope(do_QueryReferent(mScopeObject));
   return scope;
 }
@@ -5127,46 +5127,46 @@ nsDocument::DocumentStatesChanged(EventS
   // Invalidate our cached state.
   mGotDocumentState &= ~aStateMask;
   mDocumentState &= ~aStateMask;
 
   NS_DOCUMENT_NOTIFY_OBSERVERS(DocumentStatesChanged, (this, aStateMask));
 }
 
 void
-nsDocument::StyleRuleChanged(StyleSheetHandle aSheet,
+nsDocument::StyleRuleChanged(StyleSheet* aSheet,
                              css::Rule* aStyleRule)
 {
   NS_DOCUMENT_NOTIFY_OBSERVERS(StyleRuleChanged, (aSheet));
 
   if (StyleSheetChangeEventsEnabled()) {
     DO_STYLESHEET_NOTIFICATION(StyleRuleChangeEvent,
                                "StyleRuleChanged",
                                mRule,
                                aStyleRule ? aStyleRule->GetDOMRule() : nullptr);
   }
 }
 
 void
-nsDocument::StyleRuleAdded(StyleSheetHandle aSheet,
+nsDocument::StyleRuleAdded(StyleSheet* aSheet,
                            css::Rule* aStyleRule)
 {
   NS_DOCUMENT_NOTIFY_OBSERVERS(StyleRuleAdded, (aSheet));
 
   if (StyleSheetChangeEventsEnabled()) {
     DO_STYLESHEET_NOTIFICATION(StyleRuleChangeEvent,
                                "StyleRuleAdded",
                                mRule,
                                aStyleRule ? aStyleRule->GetDOMRule()
                                           : nullptr);
   }
 }
 
 void
-nsDocument::StyleRuleRemoved(StyleSheetHandle aSheet,
+nsDocument::StyleRuleRemoved(StyleSheet* aSheet,
                              css::Rule* aStyleRule)
 {
   NS_DOCUMENT_NOTIFY_OBSERVERS(StyleRuleRemoved, (aSheet));
 
   if (StyleSheetChangeEventsEnabled()) {
     DO_STYLESHEET_NOTIFICATION(StyleRuleChangeEvent,
                                "StyleRuleRemoved",
                                mRule,
@@ -6024,17 +6024,17 @@ void
 nsIDocument::GetSelectedStyleSheetSet(nsAString& aSheetSet)
 {
   aSheetSet.Truncate();
 
   // Look through our sheets, find the selected set title
   int32_t count = GetNumberOfStyleSheets();
   nsAutoString title;
   for (int32_t index = 0; index < count; index++) {
-    StyleSheetHandle sheet = GetStyleSheetAt(index);
+    StyleSheet* sheet = GetStyleSheetAt(index);
     NS_ASSERTION(sheet, "Null sheet in sheet list!");
 
     // XXXheycam Make this work with ServoStyleSheets.
     if (sheet->IsServo()) {
       NS_ERROR("stylo: can't handle alternate ServoStyleSheets yet");
       continue;
     }
 
@@ -6144,17 +6144,17 @@ nsDocument::EnableStyleSheetsForSet(cons
 void
 nsDocument::EnableStyleSheetsForSetInternal(const nsAString& aSheetSet,
                                             bool aUpdateCSSLoader)
 {
   BeginUpdate(UPDATE_STYLE);
   int32_t count = GetNumberOfStyleSheets();
   nsAutoString title;
   for (int32_t index = 0; index < count; index++) {
-    StyleSheetHandle sheet = GetStyleSheetAt(index);
+    StyleSheet* sheet = GetStyleSheetAt(index);
     NS_ASSERTION(sheet, "Null sheet in sheet list!");
 
     // XXXheycam Make this work with ServoStyleSheets.
     if (sheet->IsServo()) {
       NS_ERROR("stylo: can't handle alternate ServoStyleSheets yet");
       continue;
     }
 
@@ -9427,17 +9427,17 @@ namespace {
 /**
  * Stub for LoadSheet(), since all we want is to get the sheet into
  * the CSSLoader's style cache
  */
 class StubCSSLoaderObserver final : public nsICSSLoaderObserver {
   ~StubCSSLoaderObserver() {}
 public:
   NS_IMETHOD
-  StyleSheetLoaded(StyleSheetHandle, bool, nsresult) override
+  StyleSheetLoaded(StyleSheet*, bool, nsresult) override
   {
     return NS_OK;
   }
   NS_DECL_ISUPPORTS
 };
 NS_IMPL_ISUPPORTS(StubCSSLoaderObserver, nsICSSLoaderObserver)
 
 } // namespace
@@ -9456,17 +9456,17 @@ nsDocument::PreloadStyle(nsIURI* uri, co
                          NS_LossyConvertUTF16toASCII(charset),
                          obs,
                          Element::StringToCORSMode(aCrossOriginAttr),
                          aReferrerPolicy, aIntegrity);
 }
 
 nsresult
 nsDocument::LoadChromeSheetSync(nsIURI* uri, bool isAgentSheet,
-                                mozilla::StyleSheetHandle::RefPtr* aSheet)
+                                RefPtr<mozilla::StyleSheet>* aSheet)
 {
   css::SheetParsingMode mode =
     isAgentSheet ? css::eAgentSheetFeatures
                  : css::eAuthorSheetFeatures;
   return CSSLoader()->LoadSheetSync(uri, mode, isAgentSheet, aSheet);
 }
 
 class nsDelayedEventDispatcher : public Runnable
@@ -9792,17 +9792,17 @@ nsIDocument::CreateStaticClone(nsIDocShe
       } else {
         clonedDoc->mOriginalDocument = this;
       }
 
       clonedDoc->mOriginalDocument->mStaticCloneCount++;
 
       int32_t sheetsCount = GetNumberOfStyleSheets();
       for (int32_t i = 0; i < sheetsCount; ++i) {
-        StyleSheetHandle::RefPtr sheet = GetStyleSheetAt(i);
+        RefPtr<StyleSheet> sheet = GetStyleSheetAt(i);
         if (sheet) {
           if (sheet->IsApplicable()) {
             // XXXheycam Need to make ServoStyleSheet cloning work.
             if (sheet->IsGecko()) {
               RefPtr<CSSStyleSheet> clonedSheet =
                 sheet->AsGecko()->Clone(nullptr, nullptr, clonedDoc, nullptr);
               NS_WARNING_ASSERTION(clonedSheet,
                                    "Cloning a stylesheet didn't work!");
@@ -9812,17 +9812,17 @@ nsIDocument::CreateStaticClone(nsIDocShe
             } else {
               NS_ERROR("stylo: ServoStyleSheet doesn't support cloning");
             }
           }
         }
       }
 
       // Iterate backwards to maintain order
-      for (StyleSheetHandle sheet : Reversed(thisAsDoc->mOnDemandBuiltInUASheets)) {
+      for (StyleSheet* sheet : Reversed(thisAsDoc->mOnDemandBuiltInUASheets)) {
         if (sheet) {
           if (sheet->IsApplicable()) {
             // XXXheycam Need to make ServoStyleSheet cloning work.
             if (sheet->IsGecko()) {
               RefPtr<CSSStyleSheet> clonedSheet =
                 sheet->AsGecko()->Clone(nullptr, nullptr, clonedDoc, nullptr);
               NS_WARNING_ASSERTION(clonedSheet,
                                    "Cloning a stylesheet didn't work!");
@@ -12004,17 +12004,17 @@ nsDocument::OnAppThemeChanged()
 {
   // Bail out if there is no theme support set up properly.
   auto themeOrigin = Preferences::GetString("b2g.theme.origin");
   if (!themeOrigin || !Preferences::GetBool("dom.mozApps.themable")) {
     return;
   }
 
   for (int32_t i = 0; i < GetNumberOfStyleSheets(); i++) {
-    StyleSheetHandle::RefPtr sheet = GetStyleSheetAt(i);
+    RefPtr<StyleSheet> sheet = GetStyleSheetAt(i);
     if (!sheet) {
       continue;
     }
 
     nsINode* owningNode = sheet->GetOwnerNode();
     if (!owningNode) {
       continue;
     }
@@ -12159,22 +12159,22 @@ nsIDocument::DocAddSizeOfExcludingThis(n
 void
 nsIDocument::DocAddSizeOfIncludingThis(nsWindowSizes* aWindowSizes) const
 {
   aWindowSizes->mDOMOtherSize += aWindowSizes->mMallocSizeOf(this);
   DocAddSizeOfExcludingThis(aWindowSizes);
 }
 
 static size_t
-SizeOfOwnedSheetArrayExcludingThis(const nsTArray<StyleSheetHandle::RefPtr>& aSheets,
+SizeOfOwnedSheetArrayExcludingThis(const nsTArray<RefPtr<StyleSheet>>& aSheets,
                                    MallocSizeOf aMallocSizeOf)
 {
   size_t n = 0;
   n += aSheets.ShallowSizeOfExcludingThis(aMallocSizeOf);
-  for (StyleSheetHandle sheet : aSheets) {
+  for (StyleSheet* sheet : aSheets) {
     if (!sheet->GetOwningDocument()) {
       // Avoid over-reporting shared sheets.
       continue;
     }
     n += sheet->SizeOfIncludingThis(aMallocSizeOf);
   }
   return n;
 }

--- a/dom/base/nsDocument.h
+++ b/dom/base/nsDocument.h
@@ -616,47 +616,47 @@ public:
       nsTArray<RefPtr<mozilla::dom::Animation>>& aAnimations) override;
 
   virtual nsresult SetSubDocumentFor(Element* aContent,
                                      nsIDocument* aSubDoc) override;
   virtual nsIDocument* GetSubDocumentFor(nsIContent* aContent) const override;
   virtual Element* FindContentForSubDocument(nsIDocument *aDocument) const override;
   virtual Element* GetRootElementInternal() const override;
 
-  virtual void EnsureOnDemandBuiltInUASheet(mozilla::StyleSheetHandle aSheet) override;
+  virtual void EnsureOnDemandBuiltInUASheet(mozilla::StyleSheet* aSheet) override;
 
   /**
    * Get the (document) style sheets owned by this document.
    * These are ordered, highest priority last
    */
   virtual int32_t GetNumberOfStyleSheets() const override;
-  virtual mozilla::StyleSheetHandle GetStyleSheetAt(int32_t aIndex) const override;
+  virtual mozilla::StyleSheet* GetStyleSheetAt(int32_t aIndex) const override;
   virtual int32_t GetIndexOfStyleSheet(
-      const mozilla::StyleSheetHandle aSheet) const override;
-  virtual void AddStyleSheet(mozilla::StyleSheetHandle aSheet) override;
-  virtual void RemoveStyleSheet(mozilla::StyleSheetHandle aSheet) override;
+      const mozilla::StyleSheet* aSheet) const override;
+  virtual void AddStyleSheet(mozilla::StyleSheet* aSheet) override;
+  virtual void RemoveStyleSheet(mozilla::StyleSheet* aSheet) override;
 
   virtual void UpdateStyleSheets(
-      nsTArray<mozilla::StyleSheetHandle::RefPtr>& aOldSheets,
-      nsTArray<mozilla::StyleSheetHandle::RefPtr>& aNewSheets) override;
-  virtual void AddStyleSheetToStyleSets(mozilla::StyleSheetHandle aSheet);
-  virtual void RemoveStyleSheetFromStyleSets(mozilla::StyleSheetHandle aSheet);
+      nsTArray<RefPtr<mozilla::StyleSheet>>& aOldSheets,
+      nsTArray<RefPtr<mozilla::StyleSheet>>& aNewSheets) override;
+  virtual void AddStyleSheetToStyleSets(mozilla::StyleSheet* aSheet);
+  virtual void RemoveStyleSheetFromStyleSets(mozilla::StyleSheet* aSheet);
 
-  virtual void InsertStyleSheetAt(mozilla::StyleSheetHandle aSheet,
+  virtual void InsertStyleSheetAt(mozilla::StyleSheet* aSheet,
                                   int32_t aIndex) override;
-  virtual void SetStyleSheetApplicableState(mozilla::StyleSheetHandle aSheet,
+  virtual void SetStyleSheetApplicableState(mozilla::StyleSheet* aSheet,
                                             bool aApplicable) override;
 
   virtual nsresult LoadAdditionalStyleSheet(additionalSheetType aType,
                                             nsIURI* aSheetURI) override;
   virtual nsresult AddAdditionalStyleSheet(additionalSheetType aType,
-                                           mozilla::StyleSheetHandle aSheet) override;
+                                           mozilla::StyleSheet* aSheet) override;
   virtual void RemoveAdditionalStyleSheet(additionalSheetType aType,
                                           nsIURI* sheetURI) override;
-  virtual mozilla::StyleSheetHandle GetFirstAdditionalAuthorSheet() override;
+  virtual mozilla::StyleSheet* GetFirstAdditionalAuthorSheet() override;
 
   virtual nsIChannel* GetChannel() const override {
     return mChannel;
   }
 
   virtual nsIChannel* GetFailedChannel() const override {
     return mFailedChannel;
   }
@@ -706,21 +706,21 @@ public:
   virtual void SetReadyStateInternal(ReadyState rs) override;
 
   virtual void ContentStateChanged(nsIContent* aContent,
                                    mozilla::EventStates aStateMask)
                                      override;
   virtual void DocumentStatesChanged(
                  mozilla::EventStates aStateMask) override;
 
-  virtual void StyleRuleChanged(mozilla::StyleSheetHandle aStyleSheet,
+  virtual void StyleRuleChanged(mozilla::StyleSheet* aStyleSheet,
                                 mozilla::css::Rule* aStyleRule) override;
-  virtual void StyleRuleAdded(mozilla::StyleSheetHandle aStyleSheet,
+  virtual void StyleRuleAdded(mozilla::StyleSheet* aStyleSheet,
                               mozilla::css::Rule* aStyleRule) override;
-  virtual void StyleRuleRemoved(mozilla::StyleSheetHandle aStyleSheet,
+  virtual void StyleRuleRemoved(mozilla::StyleSheet* aStyleSheet,
                                 mozilla::css::Rule* aStyleRule) override;
 
   virtual void FlushPendingNotifications(mozFlushType aType) override;
   virtual void FlushExternalResources(mozFlushType aType) override;
   virtual void SetXMLDeclaration(const char16_t *aVersion,
                                  const char16_t *aEncoding,
                                  const int32_t aStandalone) override;
   virtual void GetXMLDeclaration(nsAString& aVersion,
@@ -782,17 +782,17 @@ public:
    * Called when an app-theme-changed observer notification is
    * received by this document.
    */
   void OnAppThemeChanged();
 
   void ReportUseCounters();
 
 private:
-  void AddOnDemandBuiltInUASheet(mozilla::StyleSheetHandle aSheet);
+  void AddOnDemandBuiltInUASheet(mozilla::StyleSheet* aSheet);
   nsRadioGroupStruct* GetRadioGroupInternal(const nsAString& aName) const;
   void SendToConsole(nsCOMArray<nsISecurityConsoleMessage>& aMessages);
 
 public:
   // nsIDOMNode
   NS_FORWARD_NSIDOMNODE_TO_NSINODE_OVERRIDABLE
 
   // nsIDOMDocument
@@ -965,17 +965,17 @@ public:
                                mozilla::CORSMode aCORSMode) override;
 
   virtual void PreloadStyle(nsIURI* uri, const nsAString& charset,
                             const nsAString& aCrossOriginAttr,
                             ReferrerPolicy aReferrerPolicy,
                             const nsAString& aIntegrity) override;
 
   virtual nsresult LoadChromeSheetSync(nsIURI* uri, bool isAgentSheet,
-                                       mozilla::StyleSheetHandle::RefPtr* aSheet) override;
+                                       RefPtr<mozilla::StyleSheet>* aSheet) override;
 
   virtual nsISupports* GetCurrentContentSink() override;
 
   virtual mozilla::EventStates GetDocumentState() override;
 
   // Only BlockOnload should call this!
   void AsyncBlockOnload();
 
@@ -1283,17 +1283,17 @@ public:
 
 protected:
   already_AddRefed<nsIPresShell> doCreateShell(nsPresContext* aContext,
                                                nsViewManager* aViewManager,
                                                mozilla::StyleSetHandle aStyleSet);
 
   void RemoveDocStyleSheetsFromStyleSets();
   void RemoveStyleSheetsFromStyleSets(
-      const nsTArray<mozilla::StyleSheetHandle::RefPtr>& aSheets,
+      const nsTArray<RefPtr<mozilla::StyleSheet>>& aSheets,
       mozilla::SheetType aType);
   void ResetStylesheetsToURI(nsIURI* aURI);
   void FillStyleSet(mozilla::StyleSetHandle aStyleSet);
 
   // Return whether all the presshells for this document are safe to flush
   bool IsSafeToFlush() const;
 
   void DispatchPageTransition(mozilla::dom::EventTarget* aDispatchTarget,
@@ -1337,19 +1337,19 @@ protected:
   // parsed into.
   nsCOMPtr<nsIParser> mParser;
 
   // Weak reference to our sink for in case we no longer have a parser.  This
   // will allow us to flush out any pending stuff from the sink even if
   // EndLoad() has already happened.
   nsWeakPtr mWeakSink;
 
-  nsTArray<mozilla::StyleSheetHandle::RefPtr> mStyleSheets;
-  nsTArray<mozilla::StyleSheetHandle::RefPtr> mOnDemandBuiltInUASheets;
-  nsTArray<mozilla::StyleSheetHandle::RefPtr> mAdditionalSheets[AdditionalSheetTypeCount];
+  nsTArray<RefPtr<mozilla::StyleSheet>> mStyleSheets;
+  nsTArray<RefPtr<mozilla::StyleSheet>> mOnDemandBuiltInUASheets;
+  nsTArray<RefPtr<mozilla::StyleSheet>> mAdditionalSheets[AdditionalSheetTypeCount];
 
   // Array of observers
   nsTObserverArray<nsIDocumentObserver*> mObservers;
 
   // Tracker for animations that are waiting to start.
   // nullptr until GetOrCreatePendingAnimationTracker is called.
   RefPtr<mozilla::PendingAnimationTracker> mPendingAnimationTracker;
 
@@ -1493,18 +1493,18 @@ public:
   mozilla::EventStates mDocumentState;
   mozilla::EventStates mGotDocumentState;
 
   RefPtr<nsDOMNavigationTiming> mTiming;
 private:
   friend class nsUnblockOnloadEvent;
   // Recomputes the visibility state but doesn't set the new value.
   mozilla::dom::VisibilityState GetVisibilityState() const;
-  void NotifyStyleSheetAdded(mozilla::StyleSheetHandle aSheet, bool aDocumentSheet);
-  void NotifyStyleSheetRemoved(mozilla::StyleSheetHandle aSheet, bool aDocumentSheet);
+  void NotifyStyleSheetAdded(mozilla::StyleSheet* aSheet, bool aDocumentSheet);
+  void NotifyStyleSheetRemoved(mozilla::StyleSheet* aSheet, bool aDocumentSheet);
 
   void PostUnblockOnloadEvent();
   void DoUnblockOnload();
 
   nsresult CheckFrameOptions();
   nsresult InitCSP(nsIChannel* aChannel);
 
   /**

--- a/dom/base/nsIDocument.h
+++ b/dom/base/nsIDocument.h
@@ -29,17 +29,17 @@
 #include "Units.h"
 #include "nsContentListDeclarations.h"
 #include "nsExpirationTracker.h"
 #include "nsClassHashtable.h"
 #include "prclist.h"
 #include "mozilla/UniquePtr.h"
 #include "mozilla/CORSMode.h"
 #include "mozilla/StyleBackendType.h"
-#include "mozilla/StyleSheetHandle.h"
+#include "mozilla/StyleSheet.h"
 #include <bitset>                        // for member
 
 #ifdef MOZILLA_INTERNAL_API
 #include "mozilla/dom/DocumentBinding.h"
 #else
 namespace mozilla {
 namespace dom {
 class ElementCreationOptionsOrString;
@@ -992,96 +992,96 @@ public:
    * This function prepends the given style sheet to the document's style set
    * in order to make sure that it does not override user-agent style sheets
    * supplied by add-ons or by the app (Firefox OS or Firefox Mobile, for
    * example), since their sheets should override built-in sheets.
    *
    * TODO We can get rid of the whole concept of delayed loading if we fix
    * bug 77999.
    */
-  virtual void EnsureOnDemandBuiltInUASheet(mozilla::StyleSheetHandle aSheet) = 0;
+  virtual void EnsureOnDemandBuiltInUASheet(mozilla::StyleSheet* aSheet) = 0;
 
   /**
    * Get the number of (document) stylesheets
    *
    * @return the number of stylesheets
    * @throws no exceptions
    */
   virtual int32_t GetNumberOfStyleSheets() const = 0;
 
   /**
    * Get a particular stylesheet
    * @param aIndex the index the stylesheet lives at.  This is zero-based
    * @return the stylesheet at aIndex.  Null if aIndex is out of range.
    * @throws no exceptions
    */
-  virtual mozilla::StyleSheetHandle GetStyleSheetAt(int32_t aIndex) const = 0;
+  virtual mozilla::StyleSheet* GetStyleSheetAt(int32_t aIndex) const = 0;
 
   /**
    * Insert a sheet at a particular spot in the stylesheet list (zero-based)
    * @param aSheet the sheet to insert
    * @param aIndex the index to insert at.  This index will be
    *   adjusted for the "special" sheets.
    * @throws no exceptions
    */
-  virtual void InsertStyleSheetAt(mozilla::StyleSheetHandle aSheet,
+  virtual void InsertStyleSheetAt(mozilla::StyleSheet* aSheet,
                                   int32_t aIndex) = 0;
 
   /**
    * Get the index of a particular stylesheet.  This will _always_
    * consider the "special" sheets as part of the sheet list.
    * @param aSheet the sheet to get the index of
    * @return aIndex the index of the sheet in the full list
    */
   virtual int32_t GetIndexOfStyleSheet(
-      const mozilla::StyleSheetHandle aSheet) const = 0;
+      const mozilla::StyleSheet* aSheet) const = 0;
 
   /**
    * Replace the stylesheets in aOldSheets with the stylesheets in
    * aNewSheets. The two lists must have equal length, and the sheet
    * at positon J in the first list will be replaced by the sheet at
    * position J in the second list.  Some sheets in the second list
    * may be null; if so the corresponding sheets in the first list
    * will simply be removed.
    */
   virtual void UpdateStyleSheets(
-      nsTArray<mozilla::StyleSheetHandle::RefPtr>& aOldSheets,
-      nsTArray<mozilla::StyleSheetHandle::RefPtr>& aNewSheets) = 0;
+      nsTArray<RefPtr<mozilla::StyleSheet>>& aOldSheets,
+      nsTArray<RefPtr<mozilla::StyleSheet>>& aNewSheets) = 0;
 
   /**
    * Add a stylesheet to the document
    */
-  virtual void AddStyleSheet(mozilla::StyleSheetHandle aSheet) = 0;
+  virtual void AddStyleSheet(mozilla::StyleSheet* aSheet) = 0;
 
   /**
    * Remove a stylesheet from the document
    */
-  virtual void RemoveStyleSheet(mozilla::StyleSheetHandle aSheet) = 0;
+  virtual void RemoveStyleSheet(mozilla::StyleSheet* aSheet) = 0;
 
   /**
    * Notify the document that the applicable state of the sheet changed
    * and that observers should be notified and style sets updated
    */
-  virtual void SetStyleSheetApplicableState(mozilla::StyleSheetHandle aSheet,
+  virtual void SetStyleSheetApplicableState(mozilla::StyleSheet* aSheet,
                                             bool aApplicable) = 0;
 
   enum additionalSheetType {
     eAgentSheet,
     eUserSheet,
     eAuthorSheet,
     AdditionalSheetTypeCount
   };
 
   virtual nsresult LoadAdditionalStyleSheet(additionalSheetType aType,
                                             nsIURI* aSheetURI) = 0;
   virtual nsresult AddAdditionalStyleSheet(additionalSheetType aType,
-                                           mozilla::StyleSheetHandle aSheet) = 0;
+                                           mozilla::StyleSheet* aSheet) = 0;
   virtual void RemoveAdditionalStyleSheet(additionalSheetType aType,
                                           nsIURI* sheetURI) = 0;
-  virtual mozilla::StyleSheetHandle GetFirstAdditionalAuthorSheet() = 0;
+  virtual mozilla::StyleSheet* GetFirstAdditionalAuthorSheet() = 0;
 
   /**
    * Assuming that aDocSheets is an array of document-level style
    * sheets for this document, returns the index that aSheet should
    * be inserted at to maintain document ordering.
    *
    * Defined in nsIDocumentInlines.h.
    */
@@ -1392,21 +1392,21 @@ public:
 
   // Notify that a document state has changed.
   // This should only be called by callers whose state is also reflected in the
   // implementation of nsDocument::GetDocumentState.
   virtual void DocumentStatesChanged(mozilla::EventStates aStateMask) = 0;
 
   // Observation hooks for style data to propagate notifications
   // to document observers
-  virtual void StyleRuleChanged(mozilla::StyleSheetHandle aStyleSheet,
+  virtual void StyleRuleChanged(mozilla::StyleSheet* aStyleSheet,
                                 mozilla::css::Rule* aStyleRule) = 0;
-  virtual void StyleRuleAdded(mozilla::StyleSheetHandle aStyleSheet,
+  virtual void StyleRuleAdded(mozilla::StyleSheet* aStyleSheet,
                               mozilla::css::Rule* aStyleRule) = 0;
-  virtual void StyleRuleRemoved(mozilla::StyleSheetHandle aStyleSheet,
+  virtual void StyleRuleRemoved(mozilla::StyleSheet* aStyleSheet,
                                 mozilla::css::Rule* aStyleRule) = 0;
 
   /**
    * Flush notifications for this document and its parent documents
    * (since those may affect the layout of this one).
    */
   virtual void FlushPendingNotifications(mozFlushType aType) = 0;
 
@@ -2204,17 +2204,17 @@ public:
    * Called by the chrome registry to load style sheets.  Can be put
    * back there if and when when that module is merged with libgklayout.
    *
    * This always does a synchronous load.  If aIsAgentSheet is true,
    * it also uses the system principal and enables unsafe rules.
    * DO NOT USE FOR UNTRUSTED CONTENT.
    */
   virtual nsresult LoadChromeSheetSync(nsIURI* aURI, bool aIsAgentSheet,
-                                       mozilla::StyleSheetHandle::RefPtr* aSheet) = 0;
+                                       RefPtr<mozilla::StyleSheet>* aSheet) = 0;
 
   /**
    * Returns true if the locale used for the document specifies a direction of
    * right to left. For chrome documents, this comes from the chrome registry.
    * This is used to determine the current state for the :-moz-locale-dir pseudoclass
    * so once can know whether a document is expected to be rendered left-to-right
    * or right-to-left.
    */

--- a/dom/base/nsIDocumentInlines.h
+++ b/dom/base/nsIDocumentInlines.h
@@ -30,17 +30,17 @@ nsIDocument::FindDocStyleSheetInsertionP
   int32_t count = aDocSheets.Length();
   int32_t index;
   for (index = 0; index < count; index++) {
     T* sheet = aDocSheets[index];
     int32_t sheetDocIndex = GetIndexOfStyleSheet(sheet);
     if (sheetDocIndex > newDocIndex)
       break;
 
-    mozilla::StyleSheetHandle sheetHandle = sheet;
+    mozilla::StyleSheet* sheetHandle = sheet;
 
     // If the sheet is not owned by the document it can be an author
     // sheet registered at nsStyleSheetService or an additional author
     // sheet on the document, which means the new
     // doc sheet should end up before it.
     if (sheetDocIndex < 0) {
       if (sheetService) {
         auto& authorSheets = *sheetService->AuthorStyleSheets();

--- a/dom/base/nsIDocumentObserver.h
+++ b/dom/base/nsIDocumentObserver.h
@@ -2,17 +2,17 @@
 /* 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 nsIDocumentObserver_h___
 #define nsIDocumentObserver_h___
 
 #include "mozilla/EventStates.h"
-#include "mozilla/StyleSheetHandle.h"
+#include "mozilla/StyleSheet.h"
 #include "nsISupports.h"
 #include "nsIMutationObserver.h"
 
 class nsIContent;
 class nsIDocument;
 
 namespace mozilla {
 namespace css {
@@ -95,75 +95,75 @@ public:
    * called automatically when a StyleSheet gets added to the
    * document, even if the stylesheet is not applicable. The
    * notification is passed on to all of the document observers.
    *
    * @param aStyleSheet the StyleSheet that has been added
    * @param aDocumentSheet True if sheet is in document's style sheet list,
    *                       false if sheet is not (i.e., UA or user sheet)
    */
-  virtual void StyleSheetAdded(mozilla::StyleSheetHandle aStyleSheet,
+  virtual void StyleSheetAdded(mozilla::StyleSheet* aStyleSheet,
                                bool aDocumentSheet) = 0;
 
   /**
    * A StyleSheet has just been removed from the document.  This
    * method is called automatically when a StyleSheet gets removed
    * from the document, even if the stylesheet is not applicable. The
    * notification is passed on to all of the document observers.
    *
    * @param aStyleSheet the StyleSheet that has been removed
    * @param aDocumentSheet True if sheet is in document's style sheet list,
    *                       false if sheet is not (i.e., UA or user sheet)
    */
-  virtual void StyleSheetRemoved(mozilla::StyleSheetHandle aStyleSheet,
+  virtual void StyleSheetRemoved(mozilla::StyleSheet* aStyleSheet,
                                  bool aDocumentSheet) = 0;
   
   /**
    * A StyleSheet has just changed its applicable state.
    * This method is called automatically when the applicable state
    * of a StyleSheet gets changed. The style sheet passes this
    * notification to the document. The notification is passed on 
    * to all of the document observers.
    *
    * @param aStyleSheet the StyleSheet that has changed state
    */
-  virtual void StyleSheetApplicableStateChanged(mozilla::StyleSheetHandle aStyleSheet) = 0;
+  virtual void StyleSheetApplicableStateChanged(mozilla::StyleSheet* aStyleSheet) = 0;
 
   /**
    * A StyleRule has just been modified within a style sheet.
    * This method is called automatically when the rule gets
    * modified. The style sheet passes this notification to 
    * the document. The notification is passed on to all of 
    * the document observers.
    *
    * @param aStyleSheet the StyleSheet that contians the rule
    */
-  virtual void StyleRuleChanged(mozilla::StyleSheetHandle aStyleSheet) = 0;
+  virtual void StyleRuleChanged(mozilla::StyleSheet* aStyleSheet) = 0;
 
   /**
    * A StyleRule has just been added to a style sheet.
    * This method is called automatically when the rule gets
    * added to the sheet. The style sheet passes this
    * notification to the document. The notification is passed on 
    * to all of the document observers.
    *
    * @param aStyleSheet the StyleSheet that has been modified
    */
-  virtual void StyleRuleAdded(mozilla::StyleSheetHandle aStyleSheet) = 0;
+  virtual void StyleRuleAdded(mozilla::StyleSheet* aStyleSheet) = 0;
 
   /**
    * A StyleRule has just been removed from a style sheet.
    * This method is called automatically when the rule gets
    * removed from the sheet. The style sheet passes this
    * notification to the document. The notification is passed on 
    * to all of the document observers.
    *
    * @param aStyleSheet the StyleSheet that has been modified
    */
-  virtual void StyleRuleRemoved(mozilla::StyleSheetHandle aStyleSheet) = 0;
+  virtual void StyleRuleRemoved(mozilla::StyleSheet* aStyleSheet) = 0;
 };
 
 NS_DEFINE_STATIC_IID_ACCESSOR(nsIDocumentObserver, NS_IDOCUMENT_OBSERVER_IID)
 
 #define NS_DECL_NSIDOCUMENTOBSERVER_BEGINUPDATE                              \
     virtual void BeginUpdate(nsIDocument* aDocument,                         \
                              nsUpdateType aUpdateType) override;
 
@@ -181,35 +181,35 @@ NS_DEFINE_STATIC_IID_ACCESSOR(nsIDocumen
                                      nsIContent* aContent,                   \
                                      mozilla::EventStates aStateMask) override;
 
 #define NS_DECL_NSIDOCUMENTOBSERVER_DOCUMENTSTATESCHANGED                    \
     virtual void DocumentStatesChanged(nsIDocument* aDocument,               \
                                        mozilla::EventStates aStateMask) override;
 
 #define NS_DECL_NSIDOCUMENTOBSERVER_STYLESHEETADDED                          \
-    virtual void StyleSheetAdded(mozilla::StyleSheetHandle aStyleSheet,      \
+    virtual void StyleSheetAdded(mozilla::StyleSheet* aStyleSheet,           \
                                  bool aDocumentSheet) override;
 
 #define NS_DECL_NSIDOCUMENTOBSERVER_STYLESHEETREMOVED                        \
-    virtual void StyleSheetRemoved(mozilla::StyleSheetHandle aStyleSheet,    \
+    virtual void StyleSheetRemoved(mozilla::StyleSheet* aStyleSheet,         \
                                    bool aDocumentSheet) override;
 
 #define NS_DECL_NSIDOCUMENTOBSERVER_STYLESHEETAPPLICABLESTATECHANGED         \
     virtual void StyleSheetApplicableStateChanged(                           \
-        mozilla::StyleSheetHandle aStyleSheet) override;
+        mozilla::StyleSheet* aStyleSheet) override;
 
 #define NS_DECL_NSIDOCUMENTOBSERVER_STYLERULECHANGED                         \
-    virtual void StyleRuleChanged(mozilla::StyleSheetHandle aStyleSheet) override;
+    virtual void StyleRuleChanged(mozilla::StyleSheet* aStyleSheet) override;
 
 #define NS_DECL_NSIDOCUMENTOBSERVER_STYLERULEADDED                           \
-    virtual void StyleRuleAdded(mozilla::StyleSheetHandle aStyleSheet) override;
+    virtual void StyleRuleAdded(mozilla::StyleSheet* aStyleSheet) override;
 
 #define NS_DECL_NSIDOCUMENTOBSERVER_STYLERULEREMOVED                         \
-    virtual void StyleRuleRemoved(mozilla::StyleSheetHandle aStyleSheet) override;
+    virtual void StyleRuleRemoved(mozilla::StyleSheet* aStyleSheet) override;
 
 #define NS_DECL_NSIDOCUMENTOBSERVER                                          \
     NS_DECL_NSIDOCUMENTOBSERVER_BEGINUPDATE                                  \
     NS_DECL_NSIDOCUMENTOBSERVER_ENDUPDATE                                    \
     NS_DECL_NSIDOCUMENTOBSERVER_BEGINLOAD                                    \
     NS_DECL_NSIDOCUMENTOBSERVER_ENDLOAD                                      \
     NS_DECL_NSIDOCUMENTOBSERVER_CONTENTSTATECHANGED                          \
     NS_DECL_NSIDOCUMENTOBSERVER_DOCUMENTSTATESCHANGED                        \
@@ -257,35 +257,35 @@ void                                    
 {                                                                         \
 }
 
 #define NS_IMPL_NSIDOCUMENTOBSERVER_CONTENT(_class)                       \
 NS_IMPL_NSIMUTATIONOBSERVER_CONTENT(_class)
 
 #define NS_IMPL_NSIDOCUMENTOBSERVER_STYLE_STUB(_class)                    \
 void                                                                      \
-_class::StyleSheetAdded(mozilla::StyleSheetHandle aStyleSheet,            \
+_class::StyleSheetAdded(mozilla::StyleSheet* aStyleSheet,                 \
                         bool aDocumentSheet)                              \
 {                                                                         \
 }                                                                         \
 void                                                                      \
-_class::StyleSheetRemoved(mozilla::StyleSheetHandle aStyleSheet,          \
+_class::StyleSheetRemoved(mozilla::StyleSheet* aStyleSheet,               \
                           bool aDocumentSheet)                            \
 {                                                                         \
 }                                                                         \
 void                                                                      \
-_class::StyleSheetApplicableStateChanged(mozilla::StyleSheetHandle aStyleSheet) \
+_class::StyleSheetApplicableStateChanged(mozilla::StyleSheet* aStyleSheet)\
 {                                                                         \
 }                                                                         \
 void                                                                      \
-_class::StyleRuleChanged(mozilla::StyleSheetHandle aStyleSheet)           \
+_class::StyleRuleChanged(mozilla::StyleSheet* aStyleSheet)                \
 {                                                                         \
 }                                                                         \
 void                                                                      \
-_class::StyleRuleAdded(mozilla::StyleSheetHandle aStyleSheet)             \
+_class::StyleRuleAdded(mozilla::StyleSheet* aStyleSheet)                  \
 {                                                                         \
 }                                                                         \
 void                                                                      \
-_class::StyleRuleRemoved(mozilla::StyleSheetHandle aStyleSheet)           \
+_class::StyleRuleRemoved(mozilla::StyleSheet* aStyleSheet)                \
 {                                                                         \
 }
 
 #endif /* nsIDocumentObserver_h___ */

--- a/dom/base/nsIStyleSheetLinkingElement.h
+++ b/dom/base/nsIStyleSheetLinkingElement.h
@@ -3,17 +3,17 @@
 /* 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 nsIStyleSheetLinkingElement_h__
 #define nsIStyleSheetLinkingElement_h__
 
 
 #include "nsISupports.h"
-#include "mozilla/StyleSheetHandle.h"
+#include "mozilla/StyleSheet.h"
 
 class nsICSSLoaderObserver;
 class nsIURI;
 
 #define NS_ISTYLESHEETLINKINGELEMENT_IID          \
 { 0xa8b79f3b, 0x9d18, 0x4f9c, \
   { 0xb1, 0xaa, 0x8c, 0x9b, 0x1b, 0xaa, 0xac, 0xad } }
 
@@ -23,24 +23,24 @@ public:
 
   /**
    * Used to make the association between a style sheet and
    * the element that linked it to the document.
    *
    * @param aStyleSheet the style sheet associated with this
    *                    element.
    */
-  NS_IMETHOD SetStyleSheet(mozilla::StyleSheetHandle aStyleSheet) = 0;
+  NS_IMETHOD SetStyleSheet(mozilla::StyleSheet* aStyleSheet) = 0;
 
   /**
    * Used to obtain the style sheet linked in by this element.
    *
    * @return the style sheet associated with this element.
    */
-  NS_IMETHOD_(mozilla::StyleSheetHandle) GetStyleSheet() = 0;
+  NS_IMETHOD_(mozilla::StyleSheet*) GetStyleSheet() = 0;
 
   /**
    * Initialize the stylesheet linking element. If aDontLoadStyle is
    * true the element will ignore the first modification to the
    * element that would cause a stylesheet to be loaded. Subsequent
    * modifications to the element will not be ignored.
    */
   NS_IMETHOD InitStyleLinkElement(bool aDontLoadStyle) = 0;

--- a/dom/base/nsStyleLinkElement.cpp
+++ b/dom/base/nsStyleLinkElement.cpp
@@ -7,18 +7,18 @@
 /*
  * A base class which implements nsIStyleSheetLinkingElement and can
  * be subclassed by various content nodes that want to load
  * stylesheets (<style>, <link>, processing instructions, etc).
  */
 
 #include "nsStyleLinkElement.h"
 
-#include "mozilla/StyleSheetHandle.h"
-#include "mozilla/StyleSheetHandleInlines.h"
+#include "mozilla/StyleSheet.h"
+#include "mozilla/StyleSheetInlines.h"
 #include "mozilla/css/Loader.h"
 #include "mozilla/dom/Element.h"
 #include "mozilla/dom/FragmentOrElement.h"
 #include "mozilla/dom/HTMLLinkElement.h"
 #include "mozilla/dom/ShadowRoot.h"
 #include "mozilla/dom/SRILogHelper.h"
 #include "mozilla/Preferences.h"
 #include "nsIContent.h"
@@ -58,34 +58,34 @@ nsStyleLinkElement::Unlink()
 void
 nsStyleLinkElement::Traverse(nsCycleCollectionTraversalCallback &cb)
 {
   nsStyleLinkElement* tmp = this;
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mStyleSheet);
 }
 
 NS_IMETHODIMP 
-nsStyleLinkElement::SetStyleSheet(StyleSheetHandle aStyleSheet)
+nsStyleLinkElement::SetStyleSheet(StyleSheet* aStyleSheet)
 {
   if (mStyleSheet) {
     mStyleSheet->SetOwningNode(nullptr);
   }
 
   mStyleSheet = aStyleSheet;
   if (mStyleSheet) {
     nsCOMPtr<nsINode> node = do_QueryObject(this);
     if (node) {
       mStyleSheet->SetOwningNode(node);
     }
   }
     
   return NS_OK;
 }
 
-NS_IMETHODIMP_(StyleSheetHandle)
+NS_IMETHODIMP_(StyleSheet*)
 nsStyleLinkElement::GetStyleSheet()
 {
   return mStyleSheet;
 }
 
 NS_IMETHODIMP 
 nsStyleLinkElement::InitStyleLinkElement(bool aDontLoadStyle)
 {

--- a/dom/base/nsStyleLinkElement.h
+++ b/dom/base/nsStyleLinkElement.h
@@ -10,17 +10,17 @@
  * stylesheets (<style>, <link>, processing instructions, etc).
  */
 
 #ifndef nsStyleLinkElement_h___
 #define nsStyleLinkElement_h___
 
 #include "mozilla/Attributes.h"
 #include "mozilla/CORSMode.h"
-#include "mozilla/CSSStyleSheet.h"
+#include "mozilla/StyleSheetInlines.h"
 #include "mozilla/net/ReferrerPolicy.h"
 #include "nsCOMPtr.h"
 #include "nsIStyleSheetLinkingElement.h"
 #include "nsTArray.h"
 
 class nsIDocument;
 class nsIURI;
 
@@ -45,18 +45,18 @@ public:
     // exposing them to script.
     NS_ASSERTION(!mStyleSheet || mStyleSheet->IsGecko(),
                  "stylo: ServoStyleSheets can't be exposed to script yet");
     return mStyleSheet && mStyleSheet->IsGecko() ? mStyleSheet->AsGecko() :
                                                    nullptr;
   }
 
   // nsIStyleSheetLinkingElement  
-  NS_IMETHOD SetStyleSheet(mozilla::StyleSheetHandle aStyleSheet) override;
-  NS_IMETHOD_(mozilla::StyleSheetHandle) GetStyleSheet() override;
+  NS_IMETHOD SetStyleSheet(mozilla::StyleSheet* aStyleSheet) override;
+  NS_IMETHOD_(mozilla::StyleSheet*) GetStyleSheet() override;
   NS_IMETHOD InitStyleLinkElement(bool aDontLoadStyle) override;
   NS_IMETHOD UpdateStyleSheet(nsICSSLoaderObserver* aObserver,
                               bool* aWillNotify,
                               bool* aIsAlternate,
                               bool aForceReload) override;
   NS_IMETHOD SetEnableUpdates(bool aEnableUpdates) override;
   NS_IMETHOD GetCharset(nsAString& aCharset) override;
 
@@ -138,17 +138,17 @@ private:
    */
   nsresult DoUpdateStyleSheet(nsIDocument* aOldDocument,
                               mozilla::dom::ShadowRoot* aOldShadowRoot,
                               nsICSSLoaderObserver* aObserver,
                               bool* aWillNotify,
                               bool* aIsAlternate,
                               bool aForceUpdate);
 
-  mozilla::StyleSheetHandle::RefPtr mStyleSheet;
+  RefPtr<mozilla::StyleSheet> mStyleSheet;
 protected:
   bool mDontLoadStyle;
   bool mUpdatesEnabled;
   uint32_t mLineNumber;
 };
 
 #endif /* nsStyleLinkElement_h___ */
 

--- a/dom/base/nsTreeSanitizer.cpp
+++ b/dom/base/nsTreeSanitizer.cpp
@@ -2,17 +2,17 @@
 /* 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 "nsTreeSanitizer.h"
 
 #include "mozilla/ArrayUtils.h"
-#include "mozilla/CSSStyleSheet.h"
+#include "mozilla/StyleSheetInlines.h"
 #include "mozilla/css/Declaration.h"
 #include "mozilla/css/StyleRule.h"
 #include "mozilla/css/Rule.h"
 #include "nsCSSParser.h"
 #include "nsCSSPropertyID.h"
 #include "nsUnicharInputStream.h"
 #include "nsIDOMCSSRule.h"
 #include "nsAttrName.h"

--- a/dom/fetch/FetchDriver.h
+++ b/dom/fetch/FetchDriver.h
@@ -7,17 +7,17 @@
 #ifndef mozilla_dom_FetchDriver_h
 #define mozilla_dom_FetchDriver_h
 
 #include "nsIChannelEventSink.h"
 #include "nsIInterfaceRequestor.h"
 #include "nsIStreamListener.h"
 #include "nsIThreadRetargetableStreamListener.h"
 #include "mozilla/ConsoleReportCollector.h"
-#include "mozilla/dom/SRICheck.h"
+#include "mozilla/dom/SRIMetadata.h"
 #include "mozilla/RefPtr.h"
 
 #include "mozilla/DebugOnly.h"
 #include "mozilla/net/ReferrerPolicy.h"
 
 class nsIConsoleReportCollector;
 class nsIDocument;
 class nsIOutputStream;

--- a/dom/html/nsHTMLDocument.cpp
+++ b/dom/html/nsHTMLDocument.cpp
@@ -109,18 +109,18 @@
 #include "mozilla/dom/HTMLDocumentBinding.h"
 #include "nsCharsetSource.h"
 #include "nsIStringBundle.h"
 #include "nsDOMClassInfo.h"
 #include "nsFocusManager.h"
 #include "nsIFrame.h"
 #include "nsIContent.h"
 #include "nsLayoutStylesheetCache.h"
-#include "mozilla/StyleSheetHandle.h"
-#include "mozilla/StyleSheetHandleInlines.h"
+#include "mozilla/StyleSheet.h"
+#include "mozilla/StyleSheetInlines.h"
 
 using namespace mozilla;
 using namespace mozilla::dom;
 
 #define NS_MAX_DOCUMENT_WRITE_DEPTH 20
 
 #include "prtime.h"
 
@@ -2545,17 +2545,17 @@ nsHTMLDocument::TearingDownEditor(nsIEdi
   if (IsEditingOn()) {
     EditingState oldState = mEditingState;
     mEditingState = eTearingDown;
 
     nsCOMPtr<nsIPresShell> presShell = GetShell();
     if (!presShell)
       return;
 
-    nsTArray<StyleSheetHandle::RefPtr> agentSheets;
+    nsTArray<RefPtr<StyleSheet>> agentSheets;
     presShell->GetAgentStyleSheets(agentSheets);
 
     auto cache = nsLayoutStylesheetCache::For(GetStyleBackendType());
 
     agentSheets.RemoveElement(cache->ContentEditableSheet());
     if (oldState == eDesignMode)
       agentSheets.RemoveElement(cache->DesignModeSheet());
 
@@ -2688,34 +2688,34 @@ nsHTMLDocument::EditingStateChanged()
     nsAutoEditingState push(this, eSettingUp);
 
     nsCOMPtr<nsIPresShell> presShell = GetShell();
     NS_ENSURE_TRUE(presShell, NS_ERROR_FAILURE);
 
     // Before making this window editable, we need to modify UA style sheet
     // because new style may change whether focused element will be focusable
     // or not.
-    nsTArray<StyleSheetHandle::RefPtr> agentSheets;
+    nsTArray<RefPtr<StyleSheet>> agentSheets;
     rv = presShell->GetAgentStyleSheets(agentSheets);
     NS_ENSURE_SUCCESS(rv, rv);
 
     auto cache = nsLayoutStylesheetCache::For(GetStyleBackendType());
 
-    StyleSheetHandle contentEditableSheet = cache->ContentEditableSheet();
+    StyleSheet* contentEditableSheet = cache->ContentEditableSheet();
 
     if (!agentSheets.Contains(contentEditableSheet)) {
       agentSheets.AppendElement(contentEditableSheet);
     }
 
     // Should we update the editable state of all the nodes in the document? We
     // need to do this when the designMode value changes, as that overrides
     // specific states on the elements.
     if (designMode) {
       // designMode is being turned on (overrides contentEditable).
-      StyleSheetHandle designModeSheet = cache->DesignModeSheet();
+      StyleSheet* designModeSheet = cache->DesignModeSheet();
       if (!agentSheets.Contains(designModeSheet)) {
         agentSheets.AppendElement(designModeSheet);
       }
 
       updateState = true;
       spellRecheckAll = oldState == eContentEditable;
     }
     else if (oldState == eDesignMode) {

--- a/dom/ipc/ContentParent.cpp
+++ b/dom/ipc/ContentParent.cpp
@@ -30,17 +30,17 @@
 #include "CrashReporterParent.h"
 #include "DeviceStorageStatics.h"
 #include "GMPServiceParent.h"
 #include "HandlerServiceParent.h"
 #include "IHistory.h"
 #include "imgIContainer.h"
 #include "mozIApplication.h"
 #include "mozilla/ClearOnShutdown.h"
-#include "mozilla/CSSStyleSheet.h"
+#include "mozilla/StyleSheetInlines.h"
 #include "mozilla/DataStorage.h"
 #include "mozilla/devtools/HeapSnapshotTempFileHelperParent.h"
 #include "mozilla/docshell/OfflineCacheUpdateParent.h"
 #include "mozilla/dom/DataTransfer.h"
 #include "mozilla/dom/DOMStorageIPC.h"
 #include "mozilla/dom/Element.h"
 #include "mozilla/dom/File.h"
 #include "mozilla/dom/ExternalHelperAppParent.h"
@@ -182,18 +182,18 @@
 #include "prio.h"
 #include "private/pprio.h"
 #include "ContentProcessManager.h"
 #include "mozilla/dom/ipc/StructuredCloneData.h"
 #include "mozilla/psm/PSMContentListener.h"
 #include "nsPluginHost.h"
 #include "nsPluginTags.h"
 #include "nsIBlocklistService.h"
-#include "mozilla/StyleSheetHandle.h"
-#include "mozilla/StyleSheetHandleInlines.h"
+#include "mozilla/StyleSheet.h"
+#include "mozilla/StyleSheetInlines.h"
 #include "nsHostObjectProtocolHandler.h"
 
 #include "nsIBidiKeyboard.h"
 
 #ifdef MOZ_WEBRTC
 #include "signaling/src/peerconnection/WebrtcGlobalParent.h"
 #endif
 
@@ -2262,29 +2262,29 @@ ContentParent::InitInternal(ProcessPrior
     Unused << SendAppInit();
   }
 
   nsStyleSheetService *sheetService = nsStyleSheetService::GetInstance();
   if (sheetService) {
     // This looks like a lot of work, but in a normal browser session we just
     // send two loads.
 
-    for (StyleSheetHandle sheet : *sheetService->AgentStyleSheets()) {
+    for (StyleSheet* sheet : *sheetService->AgentStyleSheets()) {
       URIParams uri;
       SerializeURI(sheet->GetSheetURI(), uri);
       Unused << SendLoadAndRegisterSheet(uri, nsIStyleSheetService::AGENT_SHEET);
     }
 
-    for (StyleSheetHandle sheet : *sheetService->UserStyleSheets()) {
+    for (StyleSheet* sheet : *sheetService->UserStyleSheets()) {
       URIParams uri;
       SerializeURI(sheet->GetSheetURI(), uri);
       Unused << SendLoadAndRegisterSheet(uri, nsIStyleSheetService::USER_SHEET);
     }
 
-    for (StyleSheetHandle sheet : *sheetService->AuthorStyleSheets()) {
+    for (StyleSheet* sheet : *sheetService->AuthorStyleSheets()) {
       URIParams uri;
       SerializeURI(sheet->GetSheetURI(), uri);
       Unused << SendLoadAndRegisterSheet(uri, nsIStyleSheetService::AUTHOR_SHEET);
     }
   }
 
 #ifdef MOZ_CONTENT_SANDBOX
   bool shouldSandbox = true;

--- a/dom/media/ipc/VideoDecoderManagerChild.cpp
+++ b/dom/media/ipc/VideoDecoderManagerChild.cpp
@@ -47,19 +47,19 @@ VideoDecoderManagerChild::Initialize()
       AbstractThread::CreateXPCOMThreadWrapper(childThread, false);
   }
 
   Endpoint<PVideoDecoderManagerChild> endpoint;
   if (!ContentChild::GetSingleton()->SendInitVideoDecoderManager(&endpoint)) {
     return;
   }
 
-  // TODO: The above message should return an empty endpoint if there wasn't a GPU
-  // process. Unfortunately IPDL will assert in this case, so it can't actually
-  // happen. Bug 1302009 is filed for fixing this.
+  if (!endpoint.IsValid()) {
+    return;
+  }
 
   sDecoderManager = new VideoDecoderManagerChild();
 
   RefPtr<Runnable> task = NewRunnableMethod<Endpoint<PVideoDecoderManagerChild>&&>(
     sDecoderManager, &VideoDecoderManagerChild::Open, Move(endpoint));
   sVideoDecoderChildThread->Dispatch(task.forget(), NS_DISPATCH_NORMAL);
 #else
   return;

--- a/dom/security/SRICheck.cpp
+++ b/dom/security/SRICheck.cpp
@@ -6,16 +6,17 @@
 
 #include "SRICheck.h"
 
 #include "mozilla/Base64.h"
 #include "mozilla/LoadTainting.h"
 #include "mozilla/Logging.h"
 #include "mozilla/Preferences.h"
 #include "mozilla/dom/SRILogHelper.h"
+#include "mozilla/dom/SRIMetadata.h"
 #include "nsContentUtils.h"
 #include "nsIChannel.h"
 #include "nsIConsoleReportCollector.h"
 #include "nsIProtocolHandler.h"
 #include "nsIScriptError.h"
 #include "nsIIncrementalStreamLoader.h"
 #include "nsIUnicharStreamLoader.h"
 #include "nsIURI.h"

--- a/dom/security/SRICheck.h
+++ b/dom/security/SRICheck.h
@@ -4,25 +4,26 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #ifndef mozilla_dom_SRICheck_h
 #define mozilla_dom_SRICheck_h
 
 #include "nsCOMPtr.h"
 #include "nsICryptoHash.h"
-#include "SRIMetadata.h"
 
 class nsIChannel;
 class nsIUnicharStreamLoader;
 class nsIConsoleReportCollector;
 
 namespace mozilla {
 namespace dom {
 
+class SRIMetadata;
+
 class SRICheck final
 {
 public:
   static const uint32_t MAX_METADATA_LENGTH = 24*1024;
   static const uint32_t MAX_METADATA_TOKENS = 512;
 
   /**
    * Parse the multiple hashes specified in the integrity attribute and

--- a/dom/svg/SVGDocument.cpp
+++ b/dom/svg/SVGDocument.cpp
@@ -15,18 +15,18 @@
 #include "nsNetUtil.h"
 #include "nsServiceManagerUtils.h"
 #include "nsString.h"
 #include "nsLiteralString.h"
 #include "nsIDOMSVGElement.h"
 #include "mozilla/dom/Element.h"
 #include "nsSVGElement.h"
 #include "mozilla/dom/SVGDocumentBinding.h"
-#include "mozilla/StyleSheetHandle.h"
-#include "mozilla/StyleSheetHandleInlines.h"
+#include "mozilla/StyleSheet.h"
+#include "mozilla/StyleSheetInlines.h"
 
 using namespace mozilla::css;
 using namespace mozilla::dom;
 
 namespace mozilla {
 namespace dom {
 
 //----------------------------------------------------------------------
@@ -152,33 +152,33 @@ SVGDocument::EnsureNonSVGUserAgentStyleS
           catMan->GetCategoryEntry("agent-style-sheets", name.get(),
                                    getter_Copies(spec));
 
           mozilla::css::Loader* cssLoader = CSSLoader();
           if (cssLoader->GetEnabled()) {
             nsCOMPtr<nsIURI> uri;
             NS_NewURI(getter_AddRefs(uri), spec);
             if (uri) {
-              StyleSheetHandle::RefPtr sheet;
+              RefPtr<StyleSheet> sheet;
               cssLoader->LoadSheetSync(uri,
                                        mozilla::css::eAgentSheetFeatures,
                                        true, &sheet);
               if (sheet) {
                 EnsureOnDemandBuiltInUASheet(sheet);
               }
             }
           }
         }
       }
     }
   }
 
   auto cache = nsLayoutStylesheetCache::For(GetStyleBackendType());
 
-  StyleSheetHandle sheet = cache->NumberControlSheet();
+  StyleSheet* sheet = cache->NumberControlSheet();
   if (sheet) {
     // number-control.css can be behind a pref
     EnsureOnDemandBuiltInUASheet(sheet);
   }
   EnsureOnDemandBuiltInUASheet(cache->FormsSheet());
   EnsureOnDemandBuiltInUASheet(cache->CounterStylesSheet());
   EnsureOnDemandBuiltInUASheet(cache->HTMLSheet());
   if (nsLayoutUtils::ShouldUseNoFramesSheet(this)) {

--- a/dom/xbl/nsBindingManager.cpp
+++ b/dom/xbl/nsBindingManager.cpp
@@ -765,17 +765,17 @@ nsBindingManager::MediumFeaturesChanged(
     bool thisChanged = ruleProcessor->MediumFeaturesChanged(aPresContext);
     *aRulesChanged = *aRulesChanged || thisChanged;
   }
 
   return NS_OK;
 }
 
 void
-nsBindingManager::AppendAllSheets(nsTArray<StyleSheetHandle>& aArray)
+nsBindingManager::AppendAllSheets(nsTArray<StyleSheet*>& aArray)
 {
   if (!mBoundContentSet) {
     return;
   }
 
   for (auto iter = mBoundContentSet->Iter(); !iter.Done(); iter.Next()) {
     nsIContent* boundContent = iter.Get()->GetKey();
     for (nsXBLBinding* binding = boundContent->GetXBLBinding(); binding;

--- a/dom/xbl/nsBindingManager.h
+++ b/dom/xbl/nsBindingManager.h
@@ -13,17 +13,17 @@
 #include "nsHashKeys.h"
 #include "nsInterfaceHashtable.h"
 #include "nsRefPtrHashtable.h"
 #include "nsURIHashKey.h"
 #include "nsCycleCollectionParticipant.h"
 #include "nsXBLBinding.h"
 #include "nsTArray.h"
 #include "nsThreadUtils.h"
-#include "mozilla/StyleSheetHandle.h"
+#include "mozilla/StyleSheet.h"
 
 struct ElementDependentRuleProcessorData;
 class nsIXPConnectWrappedJS;
 class nsIAtom;
 class nsIDOMNodeList;
 class nsIDocument;
 class nsIURI;
 class nsXBLDocumentInfo;
@@ -133,17 +133,17 @@ public:
   /**
    * Do any processing that needs to happen as a result of a change in
    * the characteristics of the medium, and return whether this rule
    * processor's rules have changed (e.g., because of media queries).
    */
   nsresult MediumFeaturesChanged(nsPresContext* aPresContext,
                                  bool* aRulesChanged);
 
-  void AppendAllSheets(nsTArray<mozilla::StyleSheetHandle>& aArray);
+  void AppendAllSheets(nsTArray<mozilla::StyleSheet*>& aArray);
 
   void Traverse(nsIContent *aContent,
                             nsCycleCollectionTraversalCallback &cb);
 
   NS_DECL_CYCLE_COLLECTION_CLASS(nsBindingManager)
 
   // Notify the binding manager when an outermost update begins and
   // ends.  The end method can execute script.

--- a/dom/xbl/nsXBLPrototypeBinding.cpp
+++ b/dom/xbl/nsXBLPrototypeBinding.cpp
@@ -39,18 +39,18 @@
 #include "nsIScriptError.h"
 
 #include "nsCSSRuleProcessor.h"
 #include "nsXBLResourceLoader.h"
 #include "mozilla/AddonPathService.h"
 #include "mozilla/dom/CDATASection.h"
 #include "mozilla/dom/Comment.h"
 #include "mozilla/dom/Element.h"
-#include "mozilla/StyleSheetHandle.h"
-#include "mozilla/StyleSheetHandleInlines.h"
+#include "mozilla/StyleSheet.h"
+#include "mozilla/StyleSheetInlines.h"
 
 #ifdef MOZ_XUL
 #include "nsXULElement.h"
 #endif
 
 using namespace mozilla;
 using namespace mozilla::dom;
 
@@ -1639,40 +1639,40 @@ void
 nsXBLPrototypeBinding::EnsureResources()
 {
   if (!mResources) {
     mResources = new nsXBLPrototypeResources(this);
   }
 }
 
 void
-nsXBLPrototypeBinding::AppendStyleSheet(StyleSheetHandle aSheet)
+nsXBLPrototypeBinding::AppendStyleSheet(StyleSheet* aSheet)
 {
   EnsureResources();
   mResources->AppendStyleSheet(aSheet);
 }
 
 void
-nsXBLPrototypeBinding::RemoveStyleSheet(StyleSheetHandle aSheet)
+nsXBLPrototypeBinding::RemoveStyleSheet(StyleSheet* aSheet)
 {
   if (!mResources) {
     MOZ_ASSERT(false, "Trying to remove a sheet that does not exist.");
     return;
   }
 
   mResources->RemoveStyleSheet(aSheet);
 }
 void
-nsXBLPrototypeBinding::InsertStyleSheetAt(size_t aIndex, StyleSheetHandle aSheet)
+nsXBLPrototypeBinding::InsertStyleSheetAt(size_t aIndex, StyleSheet* aSheet)
 {
   EnsureResources();
   mResources->InsertStyleSheetAt(aIndex, aSheet);
 }
 
-StyleSheetHandle
+StyleSheet*
 nsXBLPrototypeBinding::StyleSheetAt(size_t aIndex) const
 {
   MOZ_ASSERT(mResources);
   return mResources->StyleSheetAt(aIndex);
 }
 
 size_t
 nsXBLPrototypeBinding::SheetCount() const
@@ -1683,14 +1683,14 @@ nsXBLPrototypeBinding::SheetCount() cons
 bool
 nsXBLPrototypeBinding::HasStyleSheets() const
 {
   return mResources && mResources->HasStyleSheets();
 }
 
 void
 nsXBLPrototypeBinding::AppendStyleSheetsTo(
-                                      nsTArray<StyleSheetHandle>& aResult) const
+                                      nsTArray<StyleSheet*>& aResult) const
 {
   if (mResources) {
     mResources->AppendStyleSheetsTo(aResult);
   }
 }

--- a/dom/xbl/nsXBLPrototypeBinding.h
+++ b/dom/xbl/nsXBLPrototypeBinding.h
@@ -15,17 +15,17 @@
 #include "nsInterfaceHashtable.h"
 #include "nsWeakReference.h"
 #include "nsXBLDocumentInfo.h"
 #include "nsXBLProtoImpl.h"
 #include "nsXBLProtoImplMethod.h"
 #include "nsXBLPrototypeHandler.h"
 #include "nsXBLPrototypeResources.h"
 #include "mozilla/WeakPtr.h"
-#include "mozilla/StyleSheetHandle.h"
+#include "mozilla/StyleSheet.h"
 
 class nsIAtom;
 class nsIContent;
 class nsIDocument;
 class nsXBLAttributeEntry;
 class nsXBLBinding;
 class nsXBLProtoImplField;
 
@@ -115,23 +115,23 @@ public:
   void SetBasePrototype(nsXBLPrototypeBinding* aBinding);
   nsXBLPrototypeBinding* GetBasePrototype() { return mBaseBinding; }
 
   nsXBLDocumentInfo* XBLDocumentInfo() const { return mXBLDocInfoWeak; }
   bool IsChrome() { return mXBLDocInfoWeak->IsChrome(); }
 
   void SetInitialAttributes(nsIContent* aBoundElement, nsIContent* aAnonymousContent);
 
-  void AppendStyleSheet(mozilla::StyleSheetHandle aSheet);
-  void RemoveStyleSheet(mozilla::StyleSheetHandle aSheet);
-  void InsertStyleSheetAt(size_t aIndex, mozilla::StyleSheetHandle aSheet);
-  mozilla::StyleSheetHandle StyleSheetAt(size_t aIndex) const;
+  void AppendStyleSheet(mozilla::StyleSheet* aSheet);
+  void RemoveStyleSheet(mozilla::StyleSheet* aSheet);
+  void InsertStyleSheetAt(size_t aIndex, mozilla::StyleSheet* aSheet);
+  mozilla::StyleSheet* StyleSheetAt(size_t aIndex) const;
   size_t SheetCount() const;
   bool HasStyleSheets() const;
-  void AppendStyleSheetsTo(nsTArray<mozilla::StyleSheetHandle>& aResult) const;
+  void AppendStyleSheetsTo(nsTArray<mozilla::StyleSheet*>& aResult) const;
 
   nsIStyleRuleProcessor* GetRuleProcessor();
 
   nsresult FlushSkinSheets();
 
   nsIAtom* GetBaseTag(int32_t* aNamespaceID);
   void SetBaseTag(int32_t aNamespaceID, nsIAtom* aTag);
 

--- a/dom/xbl/nsXBLPrototypeResources.cpp
+++ b/dom/xbl/nsXBLPrototypeResources.cpp
@@ -14,18 +14,18 @@
 #include "nsIDocumentObserver.h"
 #include "mozilla/css/Loader.h"
 #include "nsIURI.h"
 #include "nsLayoutCID.h"
 #include "nsCSSRuleProcessor.h"
 #include "nsStyleSet.h"
 #include "mozilla/dom/URL.h"
 #include "mozilla/DebugOnly.h"
-#include "mozilla/StyleSheetHandle.h"
-#include "mozilla/StyleSheetHandleInlines.h"
+#include "mozilla/StyleSheet.h"
+#include "mozilla/StyleSheetInlines.h"
 
 using namespace mozilla;
 using mozilla::dom::IsChromeURI;
 
 nsXBLPrototypeResources::nsXBLPrototypeResources(nsXBLPrototypeBinding* aBinding)
 {
   MOZ_COUNT_CTOR(nsXBLPrototypeResources);
 
@@ -79,28 +79,28 @@ nsXBLPrototypeResources::FlushSkinSheets
   }
 
   // We have scoped stylesheets.  Reload any chrome stylesheets we
   // encounter.  (If they aren't skin sheets, it doesn't matter, since
   // they'll still be in the chrome cache.  Skip inline sheets, which
   // skin sheets can't be, and which in any case don't have a usable
   // URL to reload.)
 
-  nsTArray<StyleSheetHandle::RefPtr> oldSheets;
+  nsTArray<RefPtr<StyleSheet>> oldSheets;
 
   oldSheets.SwapElements(mStyleSheetList);
 
   mozilla::css::Loader* cssLoader = doc->CSSLoader();
 
   for (size_t i = 0, count = oldSheets.Length(); i < count; ++i) {
-    StyleSheetHandle oldSheet = oldSheets[i];
+    StyleSheet* oldSheet = oldSheets[i];
 
     nsIURI* uri = oldSheet->GetSheetURI();
 
-    StyleSheetHandle::RefPtr newSheet;
+    RefPtr<StyleSheet> newSheet;
     if (!oldSheet->IsInline() && IsChromeURI(uri)) {
       if (NS_FAILED(cssLoader->LoadSheetSync(uri, &newSheet)))
         continue;
     }
     else {
       newSheet = oldSheet;
     }
 
@@ -142,48 +142,48 @@ nsXBLPrototypeResources::ClearLoader()
 {
   mLoader = nullptr;
 }
 
 void
 nsXBLPrototypeResources::GatherRuleProcessor()
 {
   nsTArray<RefPtr<CSSStyleSheet>> sheets(mStyleSheetList.Length());
-  for (StyleSheetHandle sheet : mStyleSheetList) {
+  for (StyleSheet* sheet : mStyleSheetList) {
     MOZ_ASSERT(sheet->IsGecko(),
                "GatherRuleProcessor must only be called for "
                "nsXBLPrototypeResources objects with Gecko-flavored style "
                "backends");
     sheets.AppendElement(sheet->AsGecko());
   }
   mRuleProcessor = new nsCSSRuleProcessor(Move(sheets),
                                           SheetType::Doc,
                                           nullptr,
                                           mRuleProcessor);
 }
 
 void
-nsXBLPrototypeResources::AppendStyleSheet(StyleSheetHandle aSheet)
+nsXBLPrototypeResources::AppendStyleSheet(StyleSheet* aSheet)
 {
   mStyleSheetList.AppendElement(aSheet);
 }
 
 void
-nsXBLPrototypeResources::RemoveStyleSheet(StyleSheetHandle aSheet)
+nsXBLPrototypeResources::RemoveStyleSheet(StyleSheet* aSheet)
 {
   mStyleSheetList.RemoveElement(aSheet);
 }
 
 void
-nsXBLPrototypeResources::InsertStyleSheetAt(size_t aIndex, StyleSheetHandle aSheet)
+nsXBLPrototypeResources::InsertStyleSheetAt(size_t aIndex, StyleSheet* aSheet)
 {
   mStyleSheetList.InsertElementAt(aIndex, aSheet);
 }
 
-StyleSheetHandle
+StyleSheet*
 nsXBLPrototypeResources::StyleSheetAt(size_t aIndex) const
 {
   return mStyleSheetList[aIndex];
 }
 
 size_t
 nsXBLPrototypeResources::SheetCount() const
 {
@@ -193,12 +193,12 @@ nsXBLPrototypeResources::SheetCount() co
 bool
 nsXBLPrototypeResources::HasStyleSheets() const
 {
   return !mStyleSheetList.IsEmpty();
 }
 
 void
 nsXBLPrototypeResources::AppendStyleSheetsTo(
-                                      nsTArray<StyleSheetHandle>& aResult) const
+                                      nsTArray<StyleSheet*>& aResult) const
 {
   aResult.AppendElements(mStyleSheetList);
 }

--- a/dom/xbl/nsXBLPrototypeResources.h
+++ b/dom/xbl/nsXBLPrototypeResources.h
@@ -2,17 +2,17 @@
 /* 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 nsXBLPrototypeResources_h__
 #define nsXBLPrototypeResources_h__
 
-#include "mozilla/StyleSheetHandle.h"
+#include "mozilla/StyleSheet.h"
 #include "nsICSSLoaderObserver.h"
 
 class nsCSSRuleProcessor;
 class nsIAtom;
 class nsIContent;
 class nsXBLPrototypeBinding;
 class nsXBLResourceLoader;
 
@@ -36,37 +36,37 @@ public:
 
   nsresult Write(nsIObjectOutputStream* aStream);
 
   void Traverse(nsCycleCollectionTraversalCallback &cb);
   void Unlink();
 
   void ClearLoader();
 
-  void AppendStyleSheet(mozilla::StyleSheetHandle aSheet);
-  void RemoveStyleSheet(mozilla::StyleSheetHandle aSheet);
-  void InsertStyleSheetAt(size_t aIndex, mozilla::StyleSheetHandle aSheet);
-  mozilla::StyleSheetHandle StyleSheetAt(size_t aIndex) const;
+  void AppendStyleSheet(mozilla::StyleSheet* aSheet);
+  void RemoveStyleSheet(mozilla::StyleSheet* aSheet);
+  void InsertStyleSheetAt(size_t aIndex, mozilla::StyleSheet* aSheet);
+  mozilla::StyleSheet* StyleSheetAt(size_t aIndex) const;
   size_t SheetCount() const;
   bool HasStyleSheets() const;
-  void AppendStyleSheetsTo(nsTArray<mozilla::StyleSheetHandle>& aResult) const;
+  void AppendStyleSheetsTo(nsTArray<mozilla::StyleSheet*>& aResult) const;
 
   /**
    * Recreates mRuleProcessor to represent the current list of style sheets
    * stored in mStyleSheetList.  (Named GatherRuleProcessor to parallel
    * nsStyleSet::GatherRuleProcessors.)
    */
   void GatherRuleProcessor();
 
   nsCSSRuleProcessor* GetRuleProcessor() const { return mRuleProcessor; }
 
 private:
   // A loader object. Exists only long enough to load resources, and then it dies.
   RefPtr<nsXBLResourceLoader> mLoader;
 
   // A list of loaded stylesheets for this binding.
-  nsTArray<mozilla::StyleSheetHandle::RefPtr> mStyleSheetList;
+  nsTArray<RefPtr<mozilla::StyleSheet>> mStyleSheetList;
 
   // The list of stylesheets converted to a rule processor.
   RefPtr<nsCSSRuleProcessor> mRuleProcessor;
 };
 
 #endif

--- a/dom/xbl/nsXBLResourceLoader.cpp
+++ b/dom/xbl/nsXBLResourceLoader.cpp
@@ -12,18 +12,18 @@
 #include "nsIPresShell.h"
 #include "nsXBLService.h"
 #include "nsIServiceManager.h"
 #include "nsXBLResourceLoader.h"
 #include "nsXBLPrototypeResources.h"
 #include "nsIDocumentObserver.h"
 #include "imgILoader.h"
 #include "imgRequestProxy.h"
-#include "mozilla/StyleSheetHandle.h"
-#include "mozilla/StyleSheetHandleInlines.h"
+#include "mozilla/StyleSheet.h"
+#include "mozilla/StyleSheetInlines.h"
 #include "mozilla/css/Loader.h"
 #include "nsIURI.h"
 #include "nsNetUtil.h"
 #include "nsGkAtoms.h"
 #include "nsFrameManager.h"
 #include "nsStyleContext.h"
 #include "nsXBLPrototypeBinding.h"
 #include "nsCSSRuleProcessor.h"
@@ -130,17 +130,17 @@ nsXBLResourceLoader::LoadResources(bool*
       bool chrome;
       nsresult rv;
       if (NS_SUCCEEDED(url->SchemeIs("chrome", &chrome)) && chrome)
       {
         rv = nsContentUtils::GetSecurityManager()->
           CheckLoadURIWithPrincipal(docPrincipal, url,
                                     nsIScriptSecurityManager::ALLOW_CHROME);
         if (NS_SUCCEEDED(rv)) {
-          StyleSheetHandle::RefPtr sheet;
+          RefPtr<StyleSheet> sheet;
           rv = cssLoader->LoadSheetSync(url, &sheet);
           NS_ASSERTION(NS_SUCCEEDED(rv), "Load failed!!!");
           if (NS_SUCCEEDED(rv))
           {
             rv = StyleSheetLoaded(sheet, false, NS_OK);
             NS_ASSERTION(NS_SUCCEEDED(rv), "Processing the style sheet failed!!!");
           }
         }
@@ -159,17 +159,17 @@ nsXBLResourceLoader::LoadResources(bool*
   
   // Destroy our resource list.
   delete mResourceList;
   mResourceList = nullptr;
 }
 
 // nsICSSLoaderObserver
 NS_IMETHODIMP
-nsXBLResourceLoader::StyleSheetLoaded(StyleSheetHandle aSheet,
+nsXBLResourceLoader::StyleSheetLoaded(StyleSheet* aSheet,
                                       bool aWasAlternate,
                                       nsresult aStatus)
 {
   if (!mResources) {
     // Our resources got destroyed -- just bail out
     return NS_OK;
   }
    

--- a/dom/xbl/nsXBLResourceLoader.h
+++ b/dom/xbl/nsXBLResourceLoader.h
@@ -25,17 +25,17 @@ class nsIObjectOutputStream;
 
 class nsXBLResourceLoader : public nsICSSLoaderObserver
 {
 public:
   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
   NS_DECL_CYCLE_COLLECTION_CLASS(nsXBLResourceLoader)
 
   // nsICSSLoaderObserver
-  NS_IMETHOD StyleSheetLoaded(mozilla::StyleSheetHandle aSheet,
+  NS_IMETHOD StyleSheetLoaded(mozilla::StyleSheet* aSheet,
                               bool aWasAlternate,
                               nsresult aStatus) override;
 
   void LoadResources(bool* aResult);
   void AddResource(nsIAtom* aResourceType, const nsAString& aSrc);
   void AddResourceListener(nsIContent* aElement);
 
   nsXBLResourceLoader(nsXBLPrototypeBinding* aBinding,

--- a/dom/xml/nsXMLContentSink.cpp
+++ b/dom/xml/nsXMLContentSink.cpp
@@ -15,17 +15,17 @@
 #include "nsNetUtil.h"
 #include "nsIDocShell.h"
 #include "nsIStyleSheetLinkingElement.h"
 #include "nsIDOMComment.h"
 #include "nsIDOMCDATASection.h"
 #include "DocumentType.h"
 #include "nsHTMLParts.h"
 #include "nsCRT.h"
-#include "mozilla/CSSStyleSheet.h"
+#include "mozilla/StyleSheetInlines.h"
 #include "mozilla/css/Loader.h"
 #include "nsGkAtoms.h"
 #include "nsContentUtils.h"
 #include "nsIScriptContext.h"
 #include "nsNameSpaceManager.h"
 #include "nsIServiceManager.h"
 #include "nsIScriptSecurityManager.h"
 #include "nsIContentViewer.h"
@@ -406,17 +406,17 @@ nsXMLContentSink::OnTransformDone(nsresu
   ScrollToRef();
 
   originalDocument->EndLoad();
 
   return NS_OK;
 }
 
 NS_IMETHODIMP
-nsXMLContentSink::StyleSheetLoaded(StyleSheetHandle aSheet,
+nsXMLContentSink::StyleSheetLoaded(StyleSheet* aSheet,
                                    bool aWasAlternate,
                                    nsresult aStatus)
 {
   if (!mPrettyPrinting) {
     return nsContentSink::StyleSheetLoaded(aSheet, aWasAlternate, aStatus);
   }
 
   if (!mDocument->CSSLoader()->HasPendingLoads()) {

--- a/dom/xml/nsXMLContentSink.h
+++ b/dom/xml/nsXMLContentSink.h
@@ -77,17 +77,17 @@ public:
   virtual bool IsScriptExecuting() override;
   virtual void ContinueInterruptedParsingAsync() override;
 
   // nsITransformObserver
   NS_IMETHOD OnDocumentCreated(nsIDocument *aResultDocument) override;
   NS_IMETHOD OnTransformDone(nsresult aResult, nsIDocument *aResultDocument) override;
 
   // nsICSSLoaderObserver
-  NS_IMETHOD StyleSheetLoaded(mozilla::StyleSheetHandle aSheet,
+  NS_IMETHOD StyleSheetLoaded(mozilla::StyleSheet* aSheet,
                               bool aWasAlternate,
                               nsresult aStatus) override;
   static bool ParsePIData(const nsString &aData, nsString &aHref,
                           nsString &aTitle, nsString &aMedia,
                           bool &aIsAlternate);
 
 protected:
   virtual ~nsXMLContentSink();

--- a/dom/xslt/xslt/txMozillaXMLOutput.cpp
+++ b/dom/xslt/xslt/txMozillaXMLOutput.cpp
@@ -22,17 +22,17 @@
 #include "nsIConsoleService.h"
 #include "nsIDOMDocumentFragment.h"
 #include "nsNameSpaceManager.h"
 #include "txStringUtils.h"
 #include "txURIUtils.h"
 #include "nsIHTMLDocument.h"
 #include "nsIStyleSheetLinkingElement.h"
 #include "nsIDocumentTransformer.h"
-#include "mozilla/CSSStyleSheet.h"
+#include "mozilla/StyleSheetInlines.h"
 #include "mozilla/css/Loader.h"
 #include "mozilla/dom/Element.h"
 #include "mozilla/dom/EncodingUtils.h"
 #include "nsContentUtils.h"
 #include "txXMLUtils.h"
 #include "nsContentSink.h"
 #include "nsINode.h"
 #include "nsContentCreatorFunctions.h"
@@ -971,17 +971,17 @@ txTransformNotifier::ScriptEvaluated(nsr
     if (mScriptElements.RemoveObject(aElement)) {
         SignalTransformEnd();
     }
 
     return NS_OK;
 }
 
 NS_IMETHODIMP 
-txTransformNotifier::StyleSheetLoaded(StyleSheetHandle aSheet,
+txTransformNotifier::StyleSheetLoaded(StyleSheet* aSheet,
                                       bool aWasAlternate,
                                       nsresult aStatus)
 {
     if (mPendingStylesheetCount == 0) {
         // We weren't waiting on this stylesheet anyway.  This can happen if
         // SignalTransformEnd got called with an error aResult.  See
         // http://bugzilla.mozilla.org/show_bug.cgi?id=215465.
         return NS_OK;

--- a/dom/xslt/xslt/txMozillaXMLOutput.h
+++ b/dom/xslt/xslt/txMozillaXMLOutput.h
@@ -30,17 +30,17 @@ class txTransformNotifier final : public
 {
 public:
     txTransformNotifier();
 
     NS_DECL_ISUPPORTS
     NS_DECL_NSISCRIPTLOADEROBSERVER
     
     // nsICSSLoaderObserver
-    NS_IMETHOD StyleSheetLoaded(mozilla::StyleSheetHandle aSheet,
+    NS_IMETHOD StyleSheetLoaded(mozilla::StyleSheet* aSheet,
                                 bool aWasAlternate,
                                 nsresult aStatus) override;
 
     void Init(nsITransformObserver* aObserver);
     nsresult AddScriptElement(nsIScriptElement* aElement);
     void AddPendingStylesheet();
     void OnTransformEnd(nsresult aResult = NS_OK);
     void OnTransformStart();

--- a/dom/xul/XULDocument.cpp
+++ b/dom/xul/XULDocument.cpp
@@ -62,17 +62,17 @@
 #include "nsIScriptGlobalObject.h"
 #include "nsIScriptSecurityManager.h"
 #include "nsNodeInfoManager.h"
 #include "nsContentCreatorFunctions.h"
 #include "nsContentUtils.h"
 #include "nsIParser.h"
 #include "nsCharsetSource.h"
 #include "nsIParserService.h"
-#include "mozilla/CSSStyleSheet.h"
+#include "mozilla/StyleSheetInlines.h"
 #include "mozilla/css/Loader.h"
 #include "nsIScriptError.h"
 #include "nsIStyleSheetLinkingElement.h"
 #include "nsIObserverService.h"
 #include "nsNodeUtils.h"
 #include "nsIDocShellTreeOwner.h"
 #include "nsIXULWindow.h"
 #include "nsXULPopupManager.h"
@@ -89,18 +89,18 @@
 #include "mozilla/LoadInfo.h"
 #include "mozilla/Preferences.h"
 #include "nsTextNode.h"
 #include "nsJSUtils.h"
 #include "mozilla/dom/URL.h"
 #include "nsIContentPolicy.h"
 #include "mozAutoDocUpdate.h"
 #include "xpcpublic.h"
-#include "mozilla/StyleSheetHandle.h"
-#include "mozilla/StyleSheetHandleInlines.h"
+#include "mozilla/StyleSheet.h"
+#include "mozilla/StyleSheetInlines.h"
 
 using namespace mozilla;
 using namespace mozilla::dom;
 
 //----------------------------------------------------------------------
 //
 // CIDs
 //
@@ -3101,17 +3101,17 @@ XULDocument::DoneWalking()
             }
         }
     }
 
     return NS_OK;
 }
 
 NS_IMETHODIMP
-XULDocument::StyleSheetLoaded(StyleSheetHandle aSheet,
+XULDocument::StyleSheetLoaded(StyleSheet* aSheet,
                               bool aWasAlternate,
                               nsresult aStatus)
 {
     if (!aWasAlternate) {
         // Don't care about when alternate sheets finish loading
 
         NS_ASSERTION(mPendingSheets > 0,
             "Unexpected StyleSheetLoaded notification");
@@ -3725,17 +3725,17 @@ XULDocument::AddPrototypeSheets()
 {
     nsresult rv;
 
     const nsCOMArray<nsIURI>& sheets = mCurrentPrototype->GetStyleSheetReferences();
 
     for (int32_t i = 0; i < sheets.Count(); i++) {
         nsCOMPtr<nsIURI> uri = sheets[i];
 
-        StyleSheetHandle::RefPtr incompleteSheet;
+        RefPtr<StyleSheet> incompleteSheet;
         rv = CSSLoader()->LoadSheet(uri,
                                     mCurrentPrototype->DocumentPrincipal(),
                                     EmptyCString(), this,
                                     &incompleteSheet);
 
         // XXXldb We need to prevent bogus sheets from being held in the
         // prototype's list, but until then, don't propagate the failure
         // from LoadSheet (and thus exit the loop).

--- a/dom/xul/XULDocument.h
+++ b/dom/xul/XULDocument.h
@@ -8,17 +8,17 @@
 
 #include "nsAutoPtr.h"
 #include "nsCOMPtr.h"
 #include "nsXULPrototypeDocument.h"
 #include "nsXULPrototypeCache.h"
 #include "nsTArray.h"
 
 #include "mozilla/dom/XMLDocument.h"
-#include "mozilla/StyleSheetHandle.h"
+#include "mozilla/StyleSheet.h"
 #include "nsForwardReference.h"
 #include "nsIContent.h"
 #include "nsIDOMXULCommandDispatcher.h"
 #include "nsIDOMXULDocument.h"
 #include "nsCOMArray.h"
 #include "nsIURI.h"
 #include "nsIXULDocument.h"
 #include "nsScriptLoader.h"
@@ -158,17 +158,17 @@ public:
 
     // nsDocument interface overrides
     virtual Element* GetElementById(const nsAString & elementId) override;
 
     // nsIDOMXULDocument interface
     NS_DECL_NSIDOMXULDOCUMENT
 
     // nsICSSLoaderObserver
-    NS_IMETHOD StyleSheetLoaded(mozilla::StyleSheetHandle aSheet,
+    NS_IMETHOD StyleSheetLoaded(mozilla::StyleSheet* aSheet,
                                 bool aWasAlternate,
                                 nsresult aStatus) override;
 
     virtual void EndUpdate(nsUpdateType aUpdateType) override;
 
     virtual bool IsDocumentRightToLeft() override;
 
     virtual void ResetDocumentDirection() override;
@@ -339,17 +339,17 @@ protected:
      */
     bool                           mRestrictPersistence;
     nsTHashtable<nsStringHashKey>  mPersistenceIds;
 
     /**
      * An array of style sheets, that will be added (preserving order) to the
      * document after all of them are loaded (in DoneWalking).
      */
-    nsTArray<StyleSheetHandle::RefPtr> mOverlaySheets;
+    nsTArray<RefPtr<StyleSheet>> mOverlaySheets;
 
     nsCOMPtr<nsIDOMXULCommandDispatcher>     mCommandDispatcher; // [OWNER] of the focus tracker
 
     // Maintains the template builders that have been attached to
     // content elements
     typedef nsInterfaceHashtable<nsISupportsHashKey, nsIXULTemplateBuilder>
         BuilderTable;
     BuilderTable* mTemplateBuilderTable;

--- a/dom/xul/nsXULPrototypeCache.cpp
+++ b/dom/xul/nsXULPrototypeCache.cpp
@@ -18,17 +18,17 @@
 #include "nsIObserverService.h"
 #include "nsIStringStream.h"
 #include "nsIStorageStream.h"
 
 #include "nsAppDirectoryServiceDefs.h"
 
 #include "js/TracingAPI.h"
 
-#include "mozilla/CSSStyleSheet.h"
+#include "mozilla/StyleSheetInlines.h"
 #include "mozilla/Preferences.h"
 #include "mozilla/scache/StartupCache.h"
 #include "mozilla/scache/StartupCacheUtils.h"
 #include "mozilla/Telemetry.h"
 
 using namespace mozilla;
 using namespace mozilla::scache;
 

--- a/editor/libeditor/EditorBase.cpp
+++ b/editor/libeditor/EditorBase.cpp
@@ -4232,32 +4232,32 @@ EditorBase::CreateTxnForComposition(cons
   RefPtr<CompositionTransaction> transaction =
     new CompositionTransaction(*mIMETextNode, mIMETextOffset, mIMETextLength,
                                mComposition->GetRanges(), aStringToInsert,
                                *this);
   return transaction.forget();
 }
 
 NS_IMETHODIMP
-EditorBase::CreateTxnForAddStyleSheet(StyleSheetHandle aSheet,
+EditorBase::CreateTxnForAddStyleSheet(StyleSheet* aSheet,
                                       AddStyleSheetTransaction** aTransaction)
 {
   RefPtr<AddStyleSheetTransaction> transaction = new AddStyleSheetTransaction();
 
   nsresult rv = transaction->Init(this, aSheet);
   if (NS_SUCCEEDED(rv)) {
     transaction.forget(aTransaction);
   }
 
   return rv;
 }
 
 NS_IMETHODIMP
 EditorBase::CreateTxnForRemoveStyleSheet(
-              StyleSheetHandle aSheet,
+              StyleSheet* aSheet,
               RemoveStyleSheetTransaction** aTransaction)
 {
   RefPtr<RemoveStyleSheetTransaction> transaction =
     new RemoveStyleSheetTransaction();
 
   nsresult rv = transaction->Init(this, aSheet);
   if (NS_SUCCEEDED(rv)) {
     transaction.forget(aTransaction);

--- a/editor/libeditor/EditorBase.h
+++ b/editor/libeditor/EditorBase.h
@@ -4,17 +4,17 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #ifndef mozilla_EditorBase_h
 #define mozilla_EditorBase_h
 
 #include "mozilla/Assertions.h"         // for MOZ_ASSERT, etc.
 #include "mozilla/OwningNonNull.h"      // for OwningNonNull
 #include "mozilla/SelectionState.h"     // for RangeUpdater, etc.
-#include "mozilla/StyleSheetHandle.h"   // for StyleSheetHandle
+#include "mozilla/StyleSheet.h"   // for StyleSheet
 #include "mozilla/dom/Text.h"
 #include "nsCOMPtr.h"                   // for already_AddRefed, nsCOMPtr
 #include "nsCycleCollectionParticipant.h"
 #include "nsGkAtoms.h"
 #include "nsIEditor.h"                  // for nsIEditor::EDirection, etc.
 #include "nsIEditorIMESupport.h"        // for NS_DECL_NSIEDITORIMESUPPORT, etc.
 #include "nsIObserver.h"                // for NS_DECL_NSIOBSERVER, etc.
 #include "nsIPhonetic.h"                // for NS_DECL_NSIPHONETIC, etc.
@@ -323,24 +323,24 @@ protected:
    */
   already_AddRefed<mozilla::CompositionTransaction>
     CreateTxnForComposition(const nsAString& aStringToInsert);
 
   /**
    * Create a transaction for adding a style sheet.
    */
   NS_IMETHOD CreateTxnForAddStyleSheet(
-               StyleSheetHandle aSheet,
+               StyleSheet* aSheet,
                AddStyleSheetTransaction** aTransaction);
 
   /**
    * Create a transaction for removing a style sheet.
    */
   NS_IMETHOD CreateTxnForRemoveStyleSheet(
-               StyleSheetHandle aSheet,
+               StyleSheet* aSheet,
                RemoveStyleSheetTransaction** aTransaction);
 
   nsresult DeleteText(nsGenericDOMDataNode& aElement,
                       uint32_t aOffset, uint32_t aLength);
 
   already_AddRefed<DeleteTextTransaction>
     CreateTxnForDeleteText(nsGenericDOMDataNode& aElement,
                            uint32_t aOffset, uint32_t aLength);

--- a/editor/libeditor/HTMLEditor.cpp
+++ b/editor/libeditor/HTMLEditor.cpp
@@ -67,18 +67,18 @@
 #include "mozilla/dom/Selection.h"
 #include "mozilla/dom/DocumentFragment.h"
 #include "mozilla/dom/Element.h"
 #include "mozilla/dom/Event.h"
 #include "mozilla/dom/EventTarget.h"
 #include "mozilla/dom/HTMLBodyElement.h"
 #include "nsTextFragment.h"
 #include "nsContentList.h"
-#include "mozilla/StyleSheetHandle.h"
-#include "mozilla/StyleSheetHandleInlines.h"
+#include "mozilla/StyleSheet.h"
+#include "mozilla/StyleSheetInlines.h"
 
 namespace mozilla {
 
 using namespace dom;
 using namespace widget;
 
 // Some utilities to handle overloading of "A" tag for link and named anchor.
 static bool
@@ -2849,17 +2849,17 @@ HTMLEditor::ReplaceStyleSheet(const nsAS
 
   return ps->GetDocument()->CSSLoader()->
     LoadSheet(uaURI, false, nullptr, EmptyCString(), this);
 }
 
 NS_IMETHODIMP
 HTMLEditor::RemoveStyleSheet(const nsAString& aURL)
 {
-  StyleSheetHandle::RefPtr sheet = GetStyleSheetForURL(aURL);
+  RefPtr<StyleSheet> sheet = GetStyleSheetForURL(aURL);
   NS_ENSURE_TRUE(sheet, NS_ERROR_UNEXPECTED);
 
   RefPtr<RemoveStyleSheetTransaction> transaction;
   nsresult rv =
     CreateTxnForRemoveStyleSheet(sheet, getter_AddRefs(transaction));
   if (!transaction) {
     rv = NS_ERROR_NULL_POINTER;
   }
@@ -2889,17 +2889,17 @@ HTMLEditor::AddOverrideStyleSheet(const 
 
   nsCOMPtr<nsIURI> uaURI;
   nsresult rv = NS_NewURI(getter_AddRefs(uaURI), aURL);
   NS_ENSURE_SUCCESS(rv, rv);
 
   // We MUST ONLY load synchronous local files (no @import)
   // XXXbz Except this will actually try to load remote files
   // synchronously, of course..
-  StyleSheetHandle::RefPtr sheet;
+  RefPtr<StyleSheet> sheet;
   // Editor override style sheets may want to style Gecko anonymous boxes
   rv = ps->GetDocument()->CSSLoader()->
     LoadSheetSync(uaURI, mozilla::css::eAgentSheetFeatures, true,
                   &sheet);
 
   // Synchronous loads should ALWAYS return completed
   NS_ENSURE_TRUE(sheet, NS_ERROR_NULL_POINTER);
 
@@ -2934,17 +2934,17 @@ HTMLEditor::ReplaceOverrideStyleSheet(co
 
   return AddOverrideStyleSheet(aURL);
 }
 
 // Do NOT use transaction system for override style sheets
 NS_IMETHODIMP
 HTMLEditor::RemoveOverrideStyleSheet(const nsAString& aURL)
 {
-  StyleSheetHandle::RefPtr sheet = GetStyleSheetForURL(aURL);
+  RefPtr<StyleSheet> sheet = GetStyleSheetForURL(aURL);
 
   // Make sure we remove the stylesheet from our internal list in all
   // cases.
   nsresult rv = RemoveStyleSheetFromList(aURL);
 
   NS_ENSURE_TRUE(sheet, NS_OK); /// Don't fail if sheet not found
 
   NS_ENSURE_TRUE(mDocWeak, NS_ERROR_NOT_INITIALIZED);
@@ -2957,17 +2957,17 @@ HTMLEditor::RemoveOverrideStyleSheet(con
   // Remove it from our internal list
   return rv;
 }
 
 NS_IMETHODIMP
 HTMLEditor::EnableStyleSheet(const nsAString& aURL,
                              bool aEnable)
 {
-  StyleSheetHandle::RefPtr sheet = GetStyleSheetForURL(aURL);
+  RefPtr<StyleSheet> sheet = GetStyleSheetForURL(aURL);
   NS_ENSURE_TRUE(sheet, NS_OK); // Don't fail if sheet not found
 
   // Ensure the style sheet is owned by our document.
   nsCOMPtr<nsIDocument> doc = do_QueryReferent(mDocWeak);
   sheet->SetOwningDocument(doc);
 
   if (sheet->IsServo()) {
     // XXXheycam ServoStyleSheets don't support being enabled/disabled yet.
@@ -2975,17 +2975,17 @@ HTMLEditor::EnableStyleSheet(const nsASt
     return NS_ERROR_FAILURE;
   }
   return sheet->AsGecko()->SetDisabled(!aEnable);
 }
 
 bool
 HTMLEditor::EnableExistingStyleSheet(const nsAString& aURL)
 {
-  StyleSheetHandle::RefPtr sheet = GetStyleSheetForURL(aURL);
+  RefPtr<StyleSheet> sheet = GetStyleSheetForURL(aURL);
 
   // Enable sheet if already loaded.
   if (sheet)
   {
     // Ensure the style sheet is owned by our document.
     nsCOMPtr<nsIDocument> doc = do_QueryReferent(mDocWeak);
     sheet->SetOwningDocument(doc);
 
@@ -2997,17 +2997,17 @@ HTMLEditor::EnableExistingStyleSheet(con
     sheet->AsGecko()->SetDisabled(false);
     return true;
   }
   return false;
 }
 
 nsresult
 HTMLEditor::AddNewStyleSheetToList(const nsAString& aURL,
-                                   StyleSheetHandle aStyleSheet)
+                                   StyleSheet* aStyleSheet)
 {
   uint32_t countSS = mStyleSheets.Length();
   uint32_t countU = mStyleSheetURLs.Length();
 
   if (countSS != countU)
     return NS_ERROR_UNEXPECTED;
 
   if (!mStyleSheetURLs.AppendElement(aURL))
@@ -3027,32 +3027,32 @@ HTMLEditor::RemoveStyleSheetFromList(con
 
   // Attempt both removals; if one fails there's not much we can do.
   mStyleSheets.RemoveElementAt(foundIndex);
   mStyleSheetURLs.RemoveElementAt(foundIndex);
 
   return NS_OK;
 }
 
-StyleSheetHandle
+StyleSheet*
 HTMLEditor::GetStyleSheetForURL(const nsAString& aURL)
 {
   // is it already in the list?
   size_t foundIndex;
   foundIndex = mStyleSheetURLs.IndexOf(aURL);
   if (foundIndex == mStyleSheetURLs.NoIndex) {
     return nullptr;
   }
 
   MOZ_ASSERT(mStyleSheets[foundIndex]);
   return mStyleSheets[foundIndex];
 }
 
 void
-HTMLEditor::GetURLForStyleSheet(StyleSheetHandle aStyleSheet,
+HTMLEditor::GetURLForStyleSheet(StyleSheet* aStyleSheet,
                                 nsAString& aURL)
 {
   // is it already in the list?
   int32_t foundIndex = mStyleSheets.IndexOf(aStyleSheet);
 
   // Don't fail if we don't find it in our list
   if (foundIndex == -1)
     return;
@@ -3421,17 +3421,17 @@ HTMLEditor::DebugUnitTests(int32_t* outN
   delete tester;
   return NS_OK;
 #else
   return NS_ERROR_NOT_IMPLEMENTED;
 #endif
 }
 
 NS_IMETHODIMP
-HTMLEditor::StyleSheetLoaded(StyleSheetHandle aSheet,
+HTMLEditor::StyleSheetLoaded(StyleSheet* aSheet,
                              bool aWasAlternate,
                              nsresult aStatus)
 {
   nsresult rv = NS_OK;
   AutoEditBatch batchIt(this);
 
   if (!mLastStyleSheetURL.IsEmpty())
     RemoveStyleSheet(mLastStyleSheetURL);

--- a/editor/libeditor/HTMLEditor.h
+++ b/editor/libeditor/HTMLEditor.h
@@ -3,17 +3,17 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #ifndef mozilla_HTMLEditor_h
 #define mozilla_HTMLEditor_h
 
 #include "mozilla/Attributes.h"
 #include "mozilla/CSSEditUtils.h"
-#include "mozilla/StyleSheetHandle.h"
+#include "mozilla/StyleSheet.h"
 #include "mozilla/TextEditor.h"
 #include "mozilla/dom/Element.h"
 #include "mozilla/dom/File.h"
 
 #include "nsAttrName.h"
 #include "nsAutoPtr.h"
 #include "nsCOMPtr.h"
 #include "nsIContentFilter.h"
@@ -360,17 +360,17 @@ public:
 
   NS_IMETHOD GetIsSelectionEditable(bool* aIsSelectionEditable) override;
 
   NS_IMETHOD SelectAll() override;
 
   NS_IMETHOD GetRootElement(nsIDOMElement** aRootElement) override;
 
   // nsICSSLoaderObserver
-  NS_IMETHOD StyleSheetLoaded(StyleSheetHandle aSheet,
+  NS_IMETHOD StyleSheetLoaded(StyleSheet* aSheet,
                               bool aWasAlternate, nsresult aStatus) override;
 
   // Utility Routines, not part of public API
   NS_IMETHOD TypedText(const nsAString& aString,
                        ETypingAction aAction) override;
   nsresult InsertNodeAtPoint(nsIDOMNode* aNode,
                              nsCOMPtr<nsIDOMNode>* ioParent,
                              int32_t* ioOffset,
@@ -412,25 +412,25 @@ public:
   /**
    * Returns TRUE if sheet was loaded, false if it wasn't.
    */
   bool EnableExistingStyleSheet(const nsAString& aURL);
 
   /**
    * Dealing with the internal style sheet lists.
    */
-  StyleSheetHandle GetStyleSheetForURL(const nsAString& aURL);
-  void GetURLForStyleSheet(StyleSheetHandle aStyleSheet,
+  StyleSheet* GetStyleSheetForURL(const nsAString& aURL);
+  void GetURLForStyleSheet(StyleSheet* aStyleSheet,
                            nsAString& aURL);
 
   /**
    * Add a url + known style sheet to the internal lists.
    */
   nsresult AddNewStyleSheetToList(const nsAString &aURL,
-                                  StyleSheetHandle aStyleSheet);
+                                  StyleSheet* aStyleSheet);
   nsresult RemoveStyleSheetFromList(const nsAString &aURL);
 
   bool IsCSSEnabled()
   {
     // TODO: removal of mCSSAware and use only the presence of mCSSEditUtils
     return mCSSAware && mCSSEditUtils && mCSSEditUtils->IsCSSPrefChecked();
   }
 
@@ -902,17 +902,17 @@ protected:
   // Used by GetFirstSelectedCell and GetNextSelectedCell
   int32_t  mSelectedCellIndex;
 
   nsString mLastStyleSheetURL;
   nsString mLastOverrideStyleSheetURL;
 
   // Maintain a list of associated style sheets and their urls.
   nsTArray<nsString> mStyleSheetURLs;
-  nsTArray<StyleSheetHandle::RefPtr> mStyleSheets;
+  nsTArray<RefPtr<StyleSheet>> mStyleSheets;
 
   // an array for holding default style settings
   nsTArray<PropItem*> mDefaultStyles;
 
 protected:
   // ANONYMOUS UTILS
   void RemoveListenerAndDeleteRef(const nsAString& aEvent,
                                   nsIDOMEventListener* aListener,

--- a/editor/libeditor/StyleSheetTransactions.cpp
+++ b/editor/libeditor/StyleSheetTransactions.cpp
@@ -4,42 +4,42 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "StyleSheetTransactions.h"
 
 #include <stddef.h>                     // for nullptr
 
 #include "nsAString.h"
 #include "nsCOMPtr.h"                   // for nsCOMPtr, do_QueryInterface, etc.
-#include "mozilla/StyleSheetHandle.h"   // for mozilla::StyleSheetHandle
-#include "mozilla/StyleSheetHandleInlines.h"
+#include "mozilla/StyleSheet.h"   // for mozilla::StyleSheet
+#include "mozilla/StyleSheetInlines.h"
 #include "nsDebug.h"                    // for NS_ENSURE_TRUE
 #include "nsError.h"                    // for NS_OK, etc.
 #include "nsIDOMDocument.h"             // for nsIDOMDocument
 #include "nsIDocument.h"                // for nsIDocument
 #include "nsIDocumentObserver.h"        // for UPDATE_STYLE
 #include "nsIEditor.h"                  // for nsIEditor
 
 namespace mozilla {
 
 static void
-AddStyleSheet(nsIEditor* aEditor, StyleSheetHandle aSheet)
+AddStyleSheet(nsIEditor* aEditor, StyleSheet* aSheet)
 {
   nsCOMPtr<nsIDOMDocument> domDoc;
   aEditor->GetDocument(getter_AddRefs(domDoc));
   nsCOMPtr<nsIDocument> doc = do_QueryInterface(domDoc);
   if (doc) {
     doc->BeginUpdate(UPDATE_STYLE);
     doc->AddStyleSheet(aSheet);
     doc->EndUpdate(UPDATE_STYLE);
   }
 }
 
 static void
-RemoveStyleSheet(nsIEditor* aEditor, StyleSheetHandle aSheet)
+RemoveStyleSheet(nsIEditor* aEditor, StyleSheet* aSheet)
 {
   nsCOMPtr<nsIDOMDocument> domDoc;
   aEditor->GetDocument(getter_AddRefs(domDoc));
   nsCOMPtr<nsIDocument> doc = do_QueryInterface(domDoc);
   if (doc) {
     doc->BeginUpdate(UPDATE_STYLE);
     doc->RemoveStyleSheet(aSheet);
     doc->EndUpdate(UPDATE_STYLE);
@@ -59,17 +59,17 @@ NS_IMPL_CYCLE_COLLECTION_INHERITED(AddSt
                                    EditTransactionBase,
                                    mSheet)
 
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(AddStyleSheetTransaction)
 NS_INTERFACE_MAP_END_INHERITING(EditTransactionBase)
 
 NS_IMETHODIMP
 AddStyleSheetTransaction::Init(nsIEditor* aEditor,
-                               StyleSheetHandle aSheet)
+                               StyleSheet* aSheet)
 {
   NS_ENSURE_TRUE(aEditor && aSheet, NS_ERROR_INVALID_ARG);
 
   mEditor = aEditor;
   mSheet = aSheet;
 
   return NS_OK;
 }
@@ -113,17 +113,17 @@ NS_IMPL_CYCLE_COLLECTION_INHERITED(Remov
                                    EditTransactionBase,
                                    mSheet)
 
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(RemoveStyleSheetTransaction)
 NS_INTERFACE_MAP_END_INHERITING(EditTransactionBase)
 
 NS_IMETHODIMP
 RemoveStyleSheetTransaction::Init(nsIEditor* aEditor,
-                                  StyleSheetHandle aSheet)
+                                  StyleSheet* aSheet)
 {
   NS_ENSURE_TRUE(aEditor && aSheet, NS_ERROR_INVALID_ARG);
 
   mEditor = aEditor;
   mSheet = aSheet;
 
   return NS_OK;
 }

--- a/editor/libeditor/StyleSheetTransactions.h
+++ b/editor/libeditor/StyleSheetTransactions.h
@@ -2,72 +2,72 @@
 /* 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 StylesheetTransactions_h
 #define StylesheetTransactions_h
 
 #include "mozilla/EditTransactionBase.h" // for EditTransactionBase, etc.
-#include "mozilla/StyleSheetHandle.h"   // for mozilla::StyleSheetHandle
+#include "mozilla/StyleSheet.h"   // for mozilla::StyleSheet
 #include "nsCycleCollectionParticipant.h"
 #include "nsID.h"                       // for REFNSIID
 #include "nscore.h"                     // for NS_IMETHOD
 
 class nsIEditor;
 
 namespace mozilla {
 
 class AddStyleSheetTransaction final : public EditTransactionBase
 {
 public:
   /**
    * Initialize the transaction.
    * @param aEditor     The object providing core editing operations
    * @param aSheet      The stylesheet to add
     */
-  NS_IMETHOD Init(nsIEditor* aEditor, StyleSheetHandle aSheet);
+  NS_IMETHOD Init(nsIEditor* aEditor, StyleSheet* aSheet);
 
   AddStyleSheetTransaction();
 
   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(AddStyleSheetTransaction,
                                            EditTransactionBase)
   NS_IMETHOD QueryInterface(REFNSIID aIID, void** aInstancePtr) override;
 
   NS_DECL_EDITTRANSACTIONBASE
 
 protected:
   // The editor that created this transaction.
   nsIEditor* mEditor;
   // The style sheet to add.
-  mozilla::StyleSheetHandle::RefPtr mSheet;
+  RefPtr<mozilla::StyleSheet> mSheet;
 };
 
 
 class RemoveStyleSheetTransaction final : public EditTransactionBase
 {
 public:
   /**
    * Initialize the transaction.
    * @param aEditor     The object providing core editing operations.
    * @param aSheet      The stylesheet to remove.
    */
-  NS_IMETHOD Init(nsIEditor* aEditor, StyleSheetHandle aSheet);
+  NS_IMETHOD Init(nsIEditor* aEditor, StyleSheet* aSheet);
 
   RemoveStyleSheetTransaction();
 
   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(RemoveStyleSheetTransaction,
                                            EditTransactionBase)
   NS_IMETHOD QueryInterface(REFNSIID aIID, void** aInstancePtr) override;
 
   NS_DECL_EDITTRANSACTIONBASE
 
 protected:
   // The editor that created this transaction.
   nsIEditor* mEditor;
   // The style sheet to remove.
-  StyleSheetHandle::RefPtr mSheet;
+  RefPtr<StyleSheet> mSheet;
 
 };
 
 } // namespace mozilla
 
 #endif // #ifndef StylesheetTransactions_h

--- a/gfx/gl/GLScreenBuffer.cpp
+++ b/gfx/gl/GLScreenBuffer.cpp
@@ -10,17 +10,17 @@
 #include "GLContext.h"
 #include "GLBlitHelper.h"
 #include "GLReadTexImageHelper.h"
 #include "SharedSurfaceEGL.h"
 #include "SharedSurfaceGL.h"
 #include "ScopedGLHelpers.h"
 #include "gfx2DGlue.h"
 #include "../layers/ipc/ShadowLayers.h"
-#include "mozilla/layers/CompositableForwarder.h"
+#include "mozilla/layers/TextureForwarder.h"
 #include "mozilla/layers/TextureClientSharedSurface.h"
 
 #ifdef XP_WIN
 #include "SharedSurfaceANGLE.h"         // for SurfaceFactory_ANGLEShareHandle
 #include "SharedSurfaceD3D11Interop.h"  // for SurfaceFactory_D3D11Interop
 #include "mozilla/gfx/DeviceManagerDx.h"
 #endif
 
@@ -64,76 +64,77 @@ GLScreenBuffer::Create(GLContext* gl,
 
     ret.reset( new GLScreenBuffer(gl, caps, Move(factory)) );
     return Move(ret);
 }
 
 /* static */ UniquePtr<SurfaceFactory>
 GLScreenBuffer::CreateFactory(GLContext* gl,
                               const SurfaceCaps& caps,
-                              const RefPtr<layers::CompositableForwarder>& forwarder,
+                              KnowsCompositor* compositorConnection,
                               const layers::TextureFlags& flags)
 {
-  return CreateFactory(gl, caps, forwarder, forwarder->GetCompositorBackendType(), flags);
+  return CreateFactory(gl, caps, compositorConnection->GetTextureForwarder(),
+                       compositorConnection->GetCompositorBackendType(), flags);
 }
 
 /* static */ UniquePtr<SurfaceFactory>
 GLScreenBuffer::CreateFactory(GLContext* gl,
                               const SurfaceCaps& caps,
-                              const RefPtr<layers::ClientIPCAllocator>& allocator,
+                              LayersIPCChannel* ipcChannel,
                               const mozilla::layers::LayersBackend backend,
                               const layers::TextureFlags& flags)
 {
     UniquePtr<SurfaceFactory> factory = nullptr;
     if (!gfxPrefs::WebGLForceLayersReadback()) {
         switch (backend) {
             case mozilla::layers::LayersBackend::LAYERS_OPENGL: {
 #if defined(XP_MACOSX)
-                factory = SurfaceFactory_IOSurface::Create(gl, caps, allocator, flags);
+                factory = SurfaceFactory_IOSurface::Create(gl, caps, ipcChannel, flags);
 #elif defined(MOZ_WIDGET_GONK)
-                factory = MakeUnique<SurfaceFactory_Gralloc>(gl, caps, allocator, flags);
+                factory = MakeUnique<SurfaceFactory_Gralloc>(gl, caps, ipcChannel, flags);
 #elif defined(GL_PROVIDER_GLX)
                 if (sGLXLibrary.UseTextureFromPixmap())
-                  factory = SurfaceFactory_GLXDrawable::Create(gl, caps, allocator, flags);
+                  factory = SurfaceFactory_GLXDrawable::Create(gl, caps, ipcChannel, flags);
 #elif defined(MOZ_WIDGET_UIKIT)
-                factory = MakeUnique<SurfaceFactory_GLTexture>(mGLContext, caps, allocator, mFlags);
+                factory = MakeUnique<SurfaceFactory_GLTexture>(mGLContext, caps, ipcChannel, mFlags);
 #else
                 if (gl->GetContextType() == GLContextType::EGL) {
                     if (XRE_IsParentProcess()) {
-                        factory = SurfaceFactory_EGLImage::Create(gl, caps, allocator, flags);
+                        factory = SurfaceFactory_EGLImage::Create(gl, caps, ipcChannel, flags);
                     }
                 }
 #endif
                 break;
             }
             case mozilla::layers::LayersBackend::LAYERS_D3D11: {
 #ifdef XP_WIN
                 // Enable surface sharing only if ANGLE and compositing devices
                 // are both WARP or both not WARP
                 gfx::DeviceManagerDx* dm = gfx::DeviceManagerDx::Get();
                 if (gl->IsANGLE() &&
                     (gl->IsWARP() == dm->IsWARP()) &&
                     dm->TextureSharingWorks())
                 {
-                    factory = SurfaceFactory_ANGLEShareHandle::Create(gl, caps, allocator, flags);
+                    factory = SurfaceFactory_ANGLEShareHandle::Create(gl, caps, ipcChannel, flags);
                 }
 
                 if (!factory && gfxPrefs::WebGLDXGLEnabled()) {
-                  factory = SurfaceFactory_D3D11Interop::Create(gl, caps, allocator, flags);
+                  factory = SurfaceFactory_D3D11Interop::Create(gl, caps, ipcChannel, flags);
                 }
 #endif
               break;
             }
             default:
               break;
         }
 
 #ifdef GL_PROVIDER_GLX
         if (!factory && sGLXLibrary.UseTextureFromPixmap()) {
-            factory = SurfaceFactory_GLXDrawable::Create(gl, caps, allocator, flags);
+            factory = SurfaceFactory_GLXDrawable::Create(gl, caps, ipcChannel, flags);
         }
 #endif
     }
 
     return factory;
 }
 
 GLScreenBuffer::GLScreenBuffer(GLContext* gl,

--- a/gfx/gl/GLScreenBuffer.h
+++ b/gfx/gl/GLScreenBuffer.h
@@ -20,17 +20,18 @@
 #include "mozilla/gfx/2D.h"
 #include "mozilla/gfx/Point.h"
 #include "mozilla/UniquePtr.h"
 #include "SharedSurface.h"
 #include "SurfaceTypes.h"
 
 namespace mozilla {
 namespace layers {
-class CompositableForwarder;
+class KnowsCompositor;
+class LayersIPCChannel;
 class SharedSurfaceTextureClient;
 } // namespace layers
 
 namespace gl {
 
 class GLContext;
 class SharedSurface;
 class ShSurfHandle;
@@ -132,22 +133,22 @@ public:
     // Infallible.
     static UniquePtr<GLScreenBuffer> Create(GLContext* gl,
                                             const gfx::IntSize& size,
                                             const SurfaceCaps& caps);
 
     static UniquePtr<SurfaceFactory>
     CreateFactory(GLContext* gl,
                   const SurfaceCaps& caps,
-                  const RefPtr<layers::CompositableForwarder>& forwarder,
+                  layers::KnowsCompositor* compositorConnection,
                   const layers::TextureFlags& flags);
     static UniquePtr<SurfaceFactory>
     CreateFactory(GLContext* gl,
                   const SurfaceCaps& caps,
-                  const RefPtr<layers::ClientIPCAllocator>& allocator,
+                  layers::LayersIPCChannel* ipcChannel,
                   const mozilla::layers::LayersBackend backend,
                   const layers::TextureFlags& flags);
 
 protected:
     GLContext* const mGL; // Owns us.
 public:
     const SurfaceCaps mCaps;
 protected:

--- a/gfx/gl/SharedSurface.cpp
+++ b/gfx/gl/SharedSurface.cpp
@@ -10,16 +10,17 @@
 #include "GLContext.h"
 #include "GLReadTexImageHelper.h"
 #include "GLScreenBuffer.h"
 #include "nsThreadUtils.h"
 #include "ScopedGLHelpers.h"
 #include "SharedSurfaceGL.h"
 #include "mozilla/layers/CompositorTypes.h"
 #include "mozilla/layers/TextureClientSharedSurface.h"
+#include "mozilla/layers/TextureForwarder.h"
 #include "mozilla/Unused.h"
 
 namespace mozilla {
 namespace gl {
 
 /*static*/ void
 SharedSurface::ProdCopy(SharedSurface* src, SharedSurface* dest,
                         SurfaceFactory* factory)
@@ -282,17 +283,17 @@ ChooseBufferBits(const SurfaceCaps& caps
     } else {
         out_drawCaps->Clear();
         *out_readCaps = screenCaps;
     }
 }
 
 SurfaceFactory::SurfaceFactory(SharedSurfaceType type, GLContext* gl,
                                const SurfaceCaps& caps,
-                               const RefPtr<layers::ClientIPCAllocator>& allocator,
+                               const RefPtr<layers::LayersIPCChannel>& allocator,
                                const layers::TextureFlags& flags)
     : mType(type)
     , mGL(gl)
     , mCaps(caps)
     , mAllocator(allocator)
     , mFlags(flags)
     , mFormats(gl->ChooseGLFormats(caps))
     , mMutex("SurfaceFactor::mMutex")

--- a/gfx/gl/SharedSurface.h
+++ b/gfx/gl/SharedSurface.h
@@ -34,17 +34,17 @@ class nsIThread;
 
 namespace mozilla {
 namespace gfx {
 class DataSourceSurface;
 class DrawTarget;
 } // namespace gfx
 
 namespace layers {
-class ClientIPCAllocator;
+class LayersIPCChannel;
 class SharedSurfaceTextureClient;
 enum class TextureFlags : uint32_t;
 class SurfaceDescriptor;
 class TextureClient;
 } // namespace layers
 
 namespace gl {
 
@@ -262,28 +262,28 @@ class SurfaceFactory : public SupportsWe
 public:
     // Should use the VIRTUAL version, but it's currently incompatible
     // with SupportsWeakPtr. (bug 1049278)
     MOZ_DECLARE_WEAKREFERENCE_TYPENAME(SurfaceFactory)
 
     const SharedSurfaceType mType;
     GLContext* const mGL;
     const SurfaceCaps mCaps;
-    const RefPtr<layers::ClientIPCAllocator> mAllocator;
+    const RefPtr<layers::LayersIPCChannel> mAllocator;
     const layers::TextureFlags mFlags;
     const GLFormats mFormats;
     Mutex mMutex;
 protected:
     SurfaceCaps mDrawCaps;
     SurfaceCaps mReadCaps;
     RefQueue<layers::SharedSurfaceTextureClient> mRecycleFreePool;
     RefSet<layers::SharedSurfaceTextureClient> mRecycleTotalPool;
 
     SurfaceFactory(SharedSurfaceType type, GLContext* gl, const SurfaceCaps& caps,
-                   const RefPtr<layers::ClientIPCAllocator>& allocator,
+                   const RefPtr<layers::LayersIPCChannel>& allocator,
                    const layers::TextureFlags& flags);
 
 public:
     virtual ~SurfaceFactory();
 
     const SurfaceCaps& DrawCaps() const {
         return mDrawCaps;
     }

--- a/gfx/gl/SharedSurfaceANGLE.cpp
+++ b/gfx/gl/SharedSurfaceANGLE.cpp
@@ -315,17 +315,17 @@ SharedSurface_ANGLEShareHandle::Readback
     return true;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // Factory
 
 /*static*/ UniquePtr<SurfaceFactory_ANGLEShareHandle>
 SurfaceFactory_ANGLEShareHandle::Create(GLContext* gl, const SurfaceCaps& caps,
-                                        const RefPtr<layers::ClientIPCAllocator>& allocator,
+                                        const RefPtr<layers::LayersIPCChannel>& allocator,
                                         const layers::TextureFlags& flags)
 {
     GLLibraryEGL* egl = &sEGLLibrary;
     if (!egl)
         return nullptr;
 
     auto ext = GLLibraryEGL::ANGLE_surface_d3d_texture_2d_share_handle;
     if (!egl->IsExtensionSupported(ext))
@@ -335,17 +335,17 @@ SurfaceFactory_ANGLEShareHandle::Create(
 
     typedef SurfaceFactory_ANGLEShareHandle ptrT;
     UniquePtr<ptrT> ret( new ptrT(gl, caps, allocator, flags, egl, config) );
     return Move(ret);
 }
 
 SurfaceFactory_ANGLEShareHandle::SurfaceFactory_ANGLEShareHandle(GLContext* gl,
                                                                  const SurfaceCaps& caps,
-                                                                 const RefPtr<layers::ClientIPCAllocator>& allocator,
+                                                                 const RefPtr<layers::LayersIPCChannel>& allocator,
                                                                  const layers::TextureFlags& flags,
                                                                  GLLibraryEGL* egl,
                                                                  EGLConfig config)
     : SurfaceFactory(SharedSurfaceType::EGLSurfaceANGLE, gl, caps, allocator, flags)
     , mProdGL(gl)
     , mEGL(egl)
     , mConfig(config)
 { }

--- a/gfx/gl/SharedSurfaceANGLE.h
+++ b/gfx/gl/SharedSurfaceANGLE.h
@@ -75,22 +75,22 @@ class SurfaceFactory_ANGLEShareHandle
 protected:
     GLContext* const mProdGL;
     GLLibraryEGL* const mEGL;
     const EGLConfig mConfig;
 
 public:
     static UniquePtr<SurfaceFactory_ANGLEShareHandle> Create(GLContext* gl,
                                                              const SurfaceCaps& caps,
-                                                             const RefPtr<layers::ClientIPCAllocator>& allocator,
+                                                             const RefPtr<layers::LayersIPCChannel>& allocator,
                                                              const layers::TextureFlags& flags);
 
 protected:
     SurfaceFactory_ANGLEShareHandle(GLContext* gl, const SurfaceCaps& caps,
-                                    const RefPtr<layers::ClientIPCAllocator>& allocator,
+                                    const RefPtr<layers::LayersIPCChannel>& allocator,
                                     const layers::TextureFlags& flags, GLLibraryEGL* egl,
                                     EGLConfig config);
 
     virtual UniquePtr<SharedSurface> CreateShared(const gfx::IntSize& size) override {
         bool hasAlpha = mReadCaps.alpha;
         return SharedSurface_ANGLEShareHandle::Create(mProdGL, mConfig, size, hasAlpha);
     }
 };

--- a/gfx/gl/SharedSurfaceD3D11Interop.cpp
+++ b/gfx/gl/SharedSurfaceD3D11Interop.cpp
@@ -386,17 +386,17 @@ SharedSurface_D3D11Interop::ToSurfaceDes
     return true;
 }
 
 //////////////////////////////////////////////////////////////////////////////////////////
 // Factory
 
 /*static*/ UniquePtr<SurfaceFactory_D3D11Interop>
 SurfaceFactory_D3D11Interop::Create(GLContext* gl, const SurfaceCaps& caps,
-                                    layers::ClientIPCAllocator* allocator,
+                                    layers::LayersIPCChannel* allocator,
                                     const layers::TextureFlags& flags)
 {
     WGLLibrary* wgl = &sWGLLib;
     if (!wgl || !wgl->HasDXInterop2())
         return nullptr;
 
     const RefPtr<DXInterop2Device> interop = DXInterop2Device::Open(wgl, gl);
     if (!interop) {
@@ -406,17 +406,17 @@ SurfaceFactory_D3D11Interop::Create(GLCo
 
     typedef SurfaceFactory_D3D11Interop ptrT;
     UniquePtr<ptrT> ret(new ptrT(gl, caps, allocator, flags, interop));
     return Move(ret);
 }
 
 SurfaceFactory_D3D11Interop::SurfaceFactory_D3D11Interop(GLContext* gl,
                                                          const SurfaceCaps& caps,
-                                                         layers::ClientIPCAllocator* allocator,
+                                                         layers::LayersIPCChannel* allocator,
                                                          const layers::TextureFlags& flags,
                                                          DXInterop2Device* interop)
     : SurfaceFactory(SharedSurfaceType::DXGLInterop2, gl, caps, allocator, flags)
     , mInterop(interop)
 { }
 
 SurfaceFactory_D3D11Interop::~SurfaceFactory_D3D11Interop()
 { }

--- a/gfx/gl/SharedSurfaceD3D11Interop.h
+++ b/gfx/gl/SharedSurfaceD3D11Interop.h
@@ -70,22 +70,22 @@ public:
 class SurfaceFactory_D3D11Interop
     : public SurfaceFactory
 {
 public:
     const RefPtr<DXInterop2Device> mInterop;
 
     static UniquePtr<SurfaceFactory_D3D11Interop> Create(GLContext* gl,
                                                          const SurfaceCaps& caps,
-                                                         layers::ClientIPCAllocator* allocator,
+                                                         layers::LayersIPCChannel* allocator,
                                                          const layers::TextureFlags& flags);
 
 protected:
     SurfaceFactory_D3D11Interop(GLContext* gl, const SurfaceCaps& caps,
-                                layers::ClientIPCAllocator* allocator,
+                                layers::LayersIPCChannel* allocator,
                                 const layers::TextureFlags& flags,
                                 DXInterop2Device* interop);
 
 public:
     virtual ~SurfaceFactory_D3D11Interop() override;
 
 protected:
     virtual UniquePtr<SharedSurface> CreateShared(const gfx::IntSize& size) override {

--- a/gfx/gl/SharedSurfaceEGL.cpp
+++ b/gfx/gl/SharedSurfaceEGL.cpp
@@ -165,17 +165,17 @@ SharedSurface_EGLImage::ReadbackByShared
     MOZ_ASSERT(NS_IsMainThread());
     return sEGLLibrary.ReadbackEGLImage(mImage, out_surface);
 }
 
 ////////////////////////////////////////////////////////////////////////
 
 /*static*/ UniquePtr<SurfaceFactory_EGLImage>
 SurfaceFactory_EGLImage::Create(GLContext* prodGL, const SurfaceCaps& caps,
-                                const RefPtr<layers::ClientIPCAllocator>& allocator,
+                                const RefPtr<layers::LayersIPCChannel>& allocator,
                                 const layers::TextureFlags& flags)
 {
     EGLContext context = GLContextEGL::Cast(prodGL)->mContext;
 
     typedef SurfaceFactory_EGLImage ptrT;
     UniquePtr<ptrT> ret;
 
     GLLibraryEGL* egl = &sEGLLibrary;

--- a/gfx/gl/SharedSurfaceEGL.h
+++ b/gfx/gl/SharedSurfaceEGL.h
@@ -85,24 +85,24 @@ public:
 
 class SurfaceFactory_EGLImage
     : public SurfaceFactory
 {
 public:
     // Fallible:
     static UniquePtr<SurfaceFactory_EGLImage> Create(GLContext* prodGL,
                                                      const SurfaceCaps& caps,
-                                                     const RefPtr<layers::ClientIPCAllocator>& allocator,
+                                                     const RefPtr<layers::LayersIPCChannel>& allocator,
                                                      const layers::TextureFlags& flags);
 
 protected:
     const EGLContext mContext;
 
     SurfaceFactory_EGLImage(GLContext* prodGL, const SurfaceCaps& caps,
-                            const RefPtr<layers::ClientIPCAllocator>& allocator,
+                            const RefPtr<layers::LayersIPCChannel>& allocator,
                             const layers::TextureFlags& flags,
                             EGLContext context)
         : SurfaceFactory(SharedSurfaceType::EGLImageShare, prodGL, caps, allocator, flags)
         , mContext(context)
     { }
 
 public:
     virtual UniquePtr<SharedSurface> CreateShared(const gfx::IntSize& size) override {