Master merge

This merges master into release to replace Redwood.

# Conflicts:
#	CLOBBER
#	build/moz.configure/old.configure
#	config/milestone.txt
#	config/moz.build
#	config/system-headers
#	dom/abort/AbortController.cpp
#	dom/abort/AbortController.h
#	dom/abort/AbortSignal.cpp
#	dom/abort/AbortSignal.h
#	dom/abort/moz.build
#	dom/abort/tests/moz.build
#	dom/animation/KeyframeEffect.cpp
#	dom/base/CustomElementRegistry.cpp
#	dom/base/DocGroup.cpp
#	dom/base/ResizeObserverController.cpp
#	dom/base/ResizeObserverController.h
#	dom/base/nsContentUtils.cpp
#	dom/base/nsContentUtils.h
#	dom/base/nsDocument.cpp
#	dom/base/nsIDocument.h
#	dom/fetch/FetchObserver.cpp
#	dom/fetch/FetchObserver.h
#	dom/heapsnapshot/AutoMemMap.cpp
#	dom/heapsnapshot/AutoMemMap.h
#	dom/heapsnapshot/CoreDump.proto
#	dom/heapsnapshot/HeapSnapshot.cpp
#	dom/heapsnapshot/HeapSnapshotTempFileHelperChild.h
#	dom/heapsnapshot/HeapSnapshotTempFileHelperParent.cpp
#	dom/heapsnapshot/HeapSnapshotTempFileHelperParent.h
#	dom/heapsnapshot/PHeapSnapshotTempFileHelper.ipdl
#	dom/heapsnapshot/moz.build
#	dom/heapsnapshot/tests/gtest/moz.build
#	dom/html/nsGenericHTMLElement.h
#	dom/media/platforms/PlatformDecoderModule.h
#	dom/media/platforms/moz.build
#	dom/script/ModuleLoadRequest.cpp
#	dom/script/ModuleLoadRequest.h
#	dom/script/ModuleScript.cpp
#	dom/script/ModuleScript.h
#	dom/script/ScriptElement.cpp
#	dom/script/ScriptElement.h
#	dom/script/ScriptLoadHandler.cpp
#	dom/script/ScriptLoadHandler.h
#	dom/script/ScriptLoader.cpp
#	dom/script/ScriptLoader.h
#	dom/script/ScriptSettings.cpp
#	dom/script/ScriptSettings.h
#	dom/script/nsIScriptElement.h
#	dom/script/nsIScriptLoaderObserver.idl
#	dom/webidl/HTMLLinkElement.webidl
#	gfx/gl/moz.build
#	gfx/graphite2/src/moz.build
#	gfx/layers/moz.build
#	js/ductwork/inspector/moz.build
#	js/ductwork/moz.build
#	js/src/gc/Heap.h
#	js/src/moz.build
#	js/src/vm/UnboxedObject-inl.h
#	js/src/vm/UnboxedObject.cpp
#	js/src/vm/UnboxedObject.h
#	layout/base/crashtests/crashtests.list
#	layout/build/moz.build
#	layout/generic/AspectRatio.h
#	layout/generic/crashtests/crashtests.list
#	layout/reftests/bidi/reftest-stylo.list
#	layout/reftests/reftest-stylo.list
#	layout/reftests/table-bordercollapse/reftest.list
#	layout/reftests/writing-mode/reftest-stylo.list
#	layout/style/StyleSheet.cpp
#	layout/style/nsRuleNode.cpp
#	layout/style/nsStyleStruct.cpp
#	layout/style/nsStyleStruct.h
#	modules/libpref/init/all.js
#	nsprpub/pr/src/linking/prlink.c
#	parser/html/java/htmlparser/src/nu/validator/htmlparser/impl/AttributeName.java
#	parser/html/java/htmlparser/src/nu/validator/htmlparser/impl/ElementName.java
#	parser/html/nsHtml5AtomList.h
#	parser/html/nsHtml5AttributeName.cpp
#	parser/html/nsHtml5AttributeName.h
#	parser/html/nsHtml5ElementName.cpp
#	parser/html/nsHtml5ElementName.h
#	parser/html/nsHtml5TreeBuilderCppSupplement.h
#	parser/htmlparser/nsElementTable.cpp
#	parser/htmlparser/nsHTMLTagList.h
#	security/nss/lib/nss/nss.h
#	security/nss/lib/softoken/pkcs11.c
#	security/nss/lib/softoken/softkver.h
#	security/nss/lib/util/nssutil.h
#	testing/web-platform/tests/tools/html5lib/html5lib/html5parser.py
#	testing/web-platform/tests/tools/html5lib/html5lib/treebuilders/_base.py
#	toolkit/modules/AppConstants.jsm

1 files changed, 122 insertions, 180 deletions

diff --git a/dom/base/ChildIterator.cpp b/dom/base/ChildIterator.cpp
index d8c454ae8..829077c83 100644
--- a/dom/base/ChildIterator.cpp
+++ b/dom/base/ChildIterator.cpp
@@ -1,66 +1,31 @@
 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/* vim: set ts=8 sts=2 et sw=2 tw=80: */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
  * You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "ChildIterator.h"
 #include "nsContentUtils.h"
+#include "mozilla/dom/HTMLSlotElement.h"
 #include "mozilla/dom/XBLChildrenElement.h"
-#include "mozilla/dom/HTMLContentElement.h"
-#include "mozilla/dom/HTMLShadowElement.h"
 #include "mozilla/dom/ShadowRoot.h"
 #include "nsIAnonymousContentCreator.h"
 #include "nsIFrame.h"
 #include "nsCSSAnonBoxes.h"
+#include "nsDocument.h"
 
 namespace mozilla {
 namespace dom {
 
-class MatchedNodes {
-public:
-  explicit MatchedNodes(HTMLContentElement* aInsertionPoint)
-    : mIsContentElement(true), mContentElement(aInsertionPoint) {}
-
-  explicit MatchedNodes(XBLChildrenElement* aInsertionPoint)
-    : mIsContentElement(false), mChildrenElement(aInsertionPoint) {}
-
-  uint32_t Length() const
-  {
-    return mIsContentElement ? mContentElement->MatchedNodes().Length()
-                             : mChildrenElement->InsertedChildrenLength();
-  }
-
-  nsIContent* operator[](int32_t aIndex) const
-  {
-    return mIsContentElement ? mContentElement->MatchedNodes()[aIndex]
-                             : mChildrenElement->InsertedChild(aIndex);
-  }
-
-  bool IsEmpty() const
-  {
-    return mIsContentElement ? mContentElement->MatchedNodes().IsEmpty()
-                             : !mChildrenElement->HasInsertedChildren();
-  }
-protected:
-  bool mIsContentElement;
-  union {
-    HTMLContentElement* mContentElement;
-    XBLChildrenElement* mChildrenElement;
-  };
-};
-
-static inline MatchedNodes
-GetMatchedNodesForPoint(nsIContent* aContent)
+ExplicitChildIterator::ExplicitChildIterator(const nsIContent* aParent,
+                                             bool aStartAtBeginning)
+  : mParent(aParent),
+    mChild(nullptr),
+    mDefaultChild(nullptr),
+    mIsFirst(aStartAtBeginning),
+    mIndexInInserted(0)
 {
-  if (aContent->NodeInfo()->Equals(nsGkAtoms::children, kNameSpaceID_XBL)) {
-    // XBL case
-    return MatchedNodes(static_cast<XBLChildrenElement*>(aContent));
-  }
-
-  // Web components case
-  MOZ_ASSERT(aContent->IsHTMLElement(nsGkAtoms::content));
-  return MatchedNodes(HTMLContentElement::FromContent(aContent));
+  mParentAsSlot = nsDocument::IsWebComponentsEnabled(mParent) ?
+    HTMLSlotElement::FromContent(mParent) : nullptr;
 }
 
 nsIContent*
@@ -69,30 +34,29 @@ ExplicitChildIterator::GetNextChild()
   // If we're already in the inserted-children array, look there first
   if (mIndexInInserted) {
     MOZ_ASSERT(mChild);
-    MOZ_ASSERT(nsContentUtils::IsContentInsertionPoint(mChild));
     MOZ_ASSERT(!mDefaultChild);
 
-    MatchedNodes assignedChildren = GetMatchedNodesForPoint(mChild);
-    if (mIndexInInserted < assignedChildren.Length()) {
-      return assignedChildren[mIndexInInserted++];
-    }
-    mIndexInInserted = 0;
-    mChild = mChild->GetNextSibling();
-  } else if (mShadowIterator) {
-    // If we're inside of a <shadow> element, look through the
-    // explicit children of the projected ShadowRoot via
-    // the mShadowIterator.
-    nsIContent* nextChild = mShadowIterator->GetNextChild();
-    if (nextChild) {
-      return nextChild;
+    if (mParentAsSlot) {
+      const nsTArray<RefPtr<nsINode>>& assignedNodes =
+        mParentAsSlot->AssignedNodes();
+
+      mChild = (mIndexInInserted < assignedNodes.Length()) ?
+        assignedNodes[mIndexInInserted++]->AsContent() : nullptr;
+      return mChild;
     }
 
-    mShadowIterator = nullptr;
+    MOZ_ASSERT(mChild->IsActiveChildrenElement());
+    auto* childrenElement =
+      static_cast<XBLChildrenElement*>(mChild);
+    if (mIndexInInserted < childrenElement->InsertedChildrenLength()) {
+      return childrenElement->InsertedChild(mIndexInInserted++);
+    }
+    mIndexInInserted = 0;
     mChild = mChild->GetNextSibling();
   } else if (mDefaultChild) {
     // If we're already in default content, check if there are more nodes there
     MOZ_ASSERT(mChild);
-    MOZ_ASSERT(nsContentUtils::IsContentInsertionPoint(mChild));
+    MOZ_ASSERT(mChild->IsActiveChildrenElement());
 
     mDefaultChild = mDefaultChild->GetNextSibling();
     if (mDefaultChild) {
@@ -101,6 +65,19 @@ ExplicitChildIterator::GetNextChild()
 
     mChild = mChild->GetNextSibling();
   } else if (mIsFirst) {  // at the beginning of the child list
+    // For slot parent, iterate over assigned nodes if not empty, otherwise
+    // fall through and iterate over direct children (fallback content).
+    if (mParentAsSlot) {
+      const nsTArray<RefPtr<nsINode>>& assignedNodes =
+        mParentAsSlot->AssignedNodes();
+      if (!assignedNodes.IsEmpty()) {
+        mIndexInInserted = 1;
+        mChild = assignedNodes[0]->AsContent();
+        mIsFirst = false;
+        return mChild;
+      }
+    }
+
     mChild = mParent->GetFirstChild();
     mIsFirst = false;
   } else if (mChild) { // in the middle of the child list
@@ -110,31 +87,16 @@ ExplicitChildIterator::GetNextChild()
   // Iterate until we find a non-insertion point, or an insertion point with
   // content.
   while (mChild) {
-    // If the current child being iterated is a shadow insertion point then
-    // the iterator needs to go into the projected ShadowRoot.
-    if (ShadowRoot::IsShadowInsertionPoint(mChild)) {
-      // Look for the next child in the projected ShadowRoot for the <shadow>
-      // element.
-      HTMLShadowElement* shadowElem = HTMLShadowElement::FromContent(mChild);
-      ShadowRoot* projectedShadow = shadowElem->GetOlderShadowRoot();
-      if (projectedShadow) {
-        mShadowIterator = new ExplicitChildIterator(projectedShadow);
-        nsIContent* nextChild = mShadowIterator->GetNextChild();
-        if (nextChild) {
-          return nextChild;
-        }
-        mShadowIterator = nullptr;
-      }
-      mChild = mChild->GetNextSibling();
-    } else if (nsContentUtils::IsContentInsertionPoint(mChild)) {
+    if (mChild->IsActiveChildrenElement()) {
       // If the current child being iterated is a content insertion point
       // then the iterator needs to return the nodes distributed into
       // the content insertion point.
-      MatchedNodes assignedChildren = GetMatchedNodesForPoint(mChild);
-      if (!assignedChildren.IsEmpty()) {
+      auto* childrenElement =
+        static_cast<XBLChildrenElement*>(mChild);
+      if (childrenElement->HasInsertedChildren()) {
         // Iterate through elements projected on insertion point.
         mIndexInInserted = 1;
-        return assignedChildren[0];
+        return childrenElement->InsertedChild(0);
       }
 
       // Insertion points inside fallback/default content
@@ -192,19 +154,17 @@ FlattenedChildIterator::Init(bool aIgnoreXBL)
 }
 
 bool
-ExplicitChildIterator::Seek(nsIContent* aChildToFind)
+ExplicitChildIterator::Seek(const nsIContent* aChildToFind)
 {
   if (aChildToFind->GetParent() == mParent &&
       !aChildToFind->IsRootOfAnonymousSubtree()) {
     // Fast path: just point ourselves to aChildToFind, which is a
     // normal DOM child of ours.
-    MOZ_ASSERT(!ShadowRoot::IsShadowInsertionPoint(aChildToFind));
-    MOZ_ASSERT(!nsContentUtils::IsContentInsertionPoint(aChildToFind));
-    mChild = aChildToFind;
+    mChild = const_cast<nsIContent*>(aChildToFind);
     mIndexInInserted = 0;
-    mShadowIterator = nullptr;
     mDefaultChild = nullptr;
     mIsFirst = false;
+    MOZ_ASSERT(!mChild->IsActiveChildrenElement());
     return true;
   }
 
@@ -220,12 +180,18 @@ ExplicitChildIterator::Get() const
 {
   MOZ_ASSERT(!mIsFirst);
 
+  // When mParentAsSlot is set, mChild is always set to the current child. It
+  // does not matter whether mChild is an assigned node or a fallback content.
+  if (mParentAsSlot) {
+    return mChild;
+  }
+
   if (mIndexInInserted) {
-    MatchedNodes assignedChildren = GetMatchedNodesForPoint(mChild);
-    return assignedChildren[mIndexInInserted - 1];
-  } else if (mShadowIterator)  {
-    return mShadowIterator->Get();
+    MOZ_ASSERT(mChild->IsActiveChildrenElement());
+    auto* childrenElement = static_cast<XBLChildrenElement*>(mChild);
+    return childrenElement->InsertedChild(mIndexInInserted - 1);
   }
+
   return mDefaultChild ? mDefaultChild : mChild;
 }
 
@@ -234,20 +200,28 @@ ExplicitChildIterator::GetPreviousChild()
 {
   // If we're already in the inserted-children array, look there first
   if (mIndexInInserted) {
+
+    if (mParentAsSlot) {
+      const nsTArray<RefPtr<nsINode>>& assignedNodes =
+        mParentAsSlot->AssignedNodes();
+
+      mChild = (--mIndexInInserted) ?
+        assignedNodes[mIndexInInserted - 1]->AsContent() : nullptr;
+
+      if (!mChild) {
+        mIsFirst = true;
+      }
+      return mChild;
+    }
+
     // NB: mIndexInInserted points one past the last returned child so we need
     // to look *two* indices back in order to return the previous child.
-    MatchedNodes assignedChildren = GetMatchedNodesForPoint(mChild);
+    MOZ_ASSERT(mChild->IsActiveChildrenElement());
+    auto* childrenElement = static_cast<XBLChildrenElement*>(mChild);
     if (--mIndexInInserted) {
-      return assignedChildren[mIndexInInserted - 1];
+      return childrenElement->InsertedChild(mIndexInInserted - 1);
     }
     mChild = mChild->GetPreviousSibling();
-  } else if (mShadowIterator) {
-    nsIContent* previousChild = mShadowIterator->GetPreviousChild();
-    if (previousChild) {
-      return previousChild;
-    }
-    mShadowIterator = nullptr;
-    mChild = mChild->GetPreviousSibling();
   } else if (mDefaultChild) {
     // If we're already in default content, check if there are more nodes there
     mDefaultChild = mDefaultChild->GetPreviousSibling();
@@ -261,35 +235,32 @@ ExplicitChildIterator::GetPreviousChild()
   } else if (mChild) { // in the middle of the child list
     mChild = mChild->GetPreviousSibling();
   } else { // at the end of the child list
+    // For slot parent, iterate over assigned nodes if not empty, otherwise
+    // fall through and iterate over direct children (fallback content).
+    if (mParentAsSlot) {
+      const nsTArray<RefPtr<nsINode>>& assignedNodes =
+        mParentAsSlot->AssignedNodes();
+      if (!assignedNodes.IsEmpty()) {
+        mIndexInInserted = assignedNodes.Length();
+        mChild = assignedNodes[mIndexInInserted - 1]->AsContent();
+        return mChild;
+      }
+    }
+
     mChild = mParent->GetLastChild();
   }
 
   // Iterate until we find a non-insertion point, or an insertion point with
   // content.
   while (mChild) {
-    if (ShadowRoot::IsShadowInsertionPoint(mChild)) {
-      // If the current child being iterated is a shadow insertion point then
-      // the iterator needs to go into the projected ShadowRoot.
-      HTMLShadowElement* shadowElem = HTMLShadowElement::FromContent(mChild);
-      ShadowRoot* projectedShadow = shadowElem->GetOlderShadowRoot();
-      if (projectedShadow) {
-        // Create a ExplicitChildIterator that begins iterating from the end.
-        mShadowIterator = new ExplicitChildIterator(projectedShadow, false);
-        nsIContent* previousChild = mShadowIterator->GetPreviousChild();
-        if (previousChild) {
-          return previousChild;
-        }
-        mShadowIterator = nullptr;
-      }
-      mChild = mChild->GetPreviousSibling();
-    } else if (nsContentUtils::IsContentInsertionPoint(mChild)) {
+    if (mChild->IsActiveChildrenElement()) {
       // If the current child being iterated is a content insertion point
       // then the iterator needs to return the nodes distributed into
       // the content insertion point.
-      MatchedNodes assignedChildren = GetMatchedNodesForPoint(mChild);
-      if (!assignedChildren.IsEmpty()) {
-        mIndexInInserted = assignedChildren.Length();
-        return assignedChildren[mIndexInInserted - 1];
+      auto* childrenElement = static_cast<XBLChildrenElement*>(mChild);
+      if (childrenElement->HasInsertedChildren()) {
+        mIndexInInserted = childrenElement->InsertedChildrenLength();
+        return childrenElement->InsertedChild(mIndexInInserted - 1);
       }
 
       mDefaultChild = mChild->GetLastChild();
@@ -317,11 +288,9 @@ AllChildrenIterator::Get() const
 {
   switch (mPhase) {
     case eAtBeforeKid: {
-      nsIFrame* frame = mOriginalContent->GetPrimaryFrame();
-      MOZ_ASSERT(frame, "No frame at eAtBeforeKid phase");
-      nsIFrame* beforeFrame = nsLayoutUtils::GetBeforeFrame(frame);
-      MOZ_ASSERT(beforeFrame, "No content before frame at eAtBeforeKid phase");
-      return beforeFrame->GetContent();
+      Element* before = nsLayoutUtils::GetBeforePseudo(mOriginalContent);
+      MOZ_ASSERT(before, "No content before frame at eAtBeforeKid phase");
+      return before;
     }
 
     case eAtExplicitKids:
@@ -331,11 +300,9 @@ AllChildrenIterator::Get() const
       return mAnonKids[mAnonKidsIdx];
 
     case eAtAfterKid: {
-      nsIFrame* frame = mOriginalContent->GetPrimaryFrame();
-      MOZ_ASSERT(frame, "No frame at eAtAfterKid phase");
-      nsIFrame* afterFrame = nsLayoutUtils::GetAfterFrame(frame);
-      MOZ_ASSERT(afterFrame, "No content before frame at eAtBeforeKid phase");
-      return afterFrame->GetContent();
+      Element* after = nsLayoutUtils::GetAfterPseudo(mOriginalContent);
+      MOZ_ASSERT(after, "No content after frame at eAtAfterKid phase");
+      return after;
     }
 
     default:
@@ -345,19 +312,14 @@ AllChildrenIterator::Get() const
 
 
 bool
-AllChildrenIterator::Seek(nsIContent* aChildToFind)
+AllChildrenIterator::Seek(const nsIContent* aChildToFind)
 {
   if (mPhase == eAtBegin || mPhase == eAtBeforeKid) {
     mPhase = eAtExplicitKids;
-    nsIFrame* frame = mOriginalContent->GetPrimaryFrame();
-    if (frame) {
-      nsIFrame* beforeFrame = nsLayoutUtils::GetBeforeFrame(frame);
-      if (beforeFrame) {
-        if (beforeFrame->GetContent() == aChildToFind) {
-          mPhase = eAtBeforeKid;
-          return true;
-        }
-      }
+    Element* beforePseudo = nsLayoutUtils::GetBeforePseudo(mOriginalContent);
+    if (beforePseudo && beforePseudo == aChildToFind) {
+      mPhase = eAtBeforeKid;
+      return true;
     }
   }
 
@@ -383,12 +345,10 @@ AllChildrenIterator::AppendNativeAnonymousChildren()
 
   // The root scroll frame is not the primary frame of the root element.
   // Detect and handle this case.
-  if (mOriginalContent == mOriginalContent->OwnerDoc()->GetRootElement()) {
-    nsIPresShell* presShell = mOriginalContent->OwnerDoc()->GetShell();
-    nsIFrame* scrollFrame = presShell ? presShell->GetRootScrollFrame() : nullptr;
-    if (scrollFrame) {
-      AppendNativeAnonymousChildrenFromFrame(scrollFrame);
-    }
+  if (!(mFlags & nsIContent::eSkipDocumentLevelNativeAnonymousContent) &&
+      mOriginalContent == mOriginalContent->OwnerDoc()->GetRootElement()) {
+    nsContentUtils::AppendDocumentLevelNativeAnonymousContentTo(
+        mOriginalContent->OwnerDoc(), mAnonKids);
   }
 }
 
@@ -406,13 +366,10 @@ AllChildrenIterator::GetNextChild()
 {
   if (mPhase == eAtBegin) {
     mPhase = eAtExplicitKids;
-    nsIFrame* frame = mOriginalContent->GetPrimaryFrame();
-    if (frame) {
-      nsIFrame* beforeFrame = nsLayoutUtils::GetBeforeFrame(frame);
-      if (beforeFrame) {
-        mPhase = eAtBeforeKid;
-        return beforeFrame->GetContent();
-      }
+    Element* beforeContent = nsLayoutUtils::GetBeforePseudo(mOriginalContent);
+    if (beforeContent) {
+      mPhase = eAtBeforeKid;
+      return beforeContent;
     }
   }
 
@@ -448,13 +405,10 @@ AllChildrenIterator::GetNextChild()
       return mAnonKids[mAnonKidsIdx];
     }
 
-    nsIFrame* frame = mOriginalContent->GetPrimaryFrame();
-    if (frame) {
-      nsIFrame* afterFrame = nsLayoutUtils::GetAfterFrame(frame);
-      if (afterFrame) {
-        mPhase = eAtAfterKid;
-        return afterFrame->GetContent();
-      }
+    Element* afterContent = nsLayoutUtils::GetAfterPseudo(mOriginalContent);
+    if (afterContent) {
+      mPhase = eAtAfterKid;
+      return afterContent;
     }
   }
 
@@ -468,13 +422,10 @@ AllChildrenIterator::GetPreviousChild()
   if (mPhase == eAtEnd) {
     MOZ_ASSERT(mAnonKidsIdx == mAnonKids.Length());
     mPhase = eAtAnonKids;
-    nsIFrame* frame = mOriginalContent->GetPrimaryFrame();
-    if (frame) {
-      nsIFrame* afterFrame = nsLayoutUtils::GetAfterFrame(frame);
-      if (afterFrame) {
-        mPhase = eAtAfterKid;
-        return afterFrame->GetContent();
-      }
+    Element* afterContent = nsLayoutUtils::GetAfterPseudo(mOriginalContent);
+    if (afterContent) {
+      mPhase = eAtAfterKid;
+      return afterContent;
     }
   }
 
@@ -503,13 +454,10 @@ AllChildrenIterator::GetPreviousChild()
       return kid;
     }
 
-    nsIFrame* frame = mOriginalContent->GetPrimaryFrame();
-    if (frame) {
-      nsIFrame* beforeFrame = nsLayoutUtils::GetBeforeFrame(frame);
-      if (beforeFrame) {
-        mPhase = eAtBeforeKid;
-        return beforeFrame->GetContent();
-      }
+    Element* beforeContent = nsLayoutUtils::GetBeforePseudo(mOriginalContent);
+    if (beforeContent) {
+      mPhase = eAtBeforeKid;
+      return beforeContent;
     }
   }
 
@@ -585,12 +533,6 @@ StyleChildrenIterator::IsNeeded(const Element* aElement)
     return true;
   }
 
-  // The root element has a scroll frame that is not the primary frame, so we
-  // need to do special checking for that case.
-  if (aElement == aElement->OwnerDoc()->GetRootElement()) {
-    return true;
-  }
-
   return false;
 }