Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 3254 insertions, 0 deletions

diff --git a/dom/base/nsRange.cpp b/dom/base/nsRange.cpp
new file mode 100644
index 0000000000..3121ed86c3
--- /dev/null
+++ b/dom/base/nsRange.cpp
@@ -0,0 +1,3254 @@
+/* -*- 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/. */
+
+/*
+ * Implementation of the DOM Range object.
+ */
+
+#include "RangeBoundary.h"
+#include "nscore.h"
+#include "nsRange.h"
+
+#include "nsDebug.h"
+#include "nsString.h"
+#include "nsReadableUtils.h"
+#include "nsIContent.h"
+#include "mozilla/dom/Document.h"
+#include "nsError.h"
+#include "nsINodeList.h"
+#include "nsGkAtoms.h"
+#include "nsContentUtils.h"
+#include "nsFrameSelection.h"
+#include "nsLayoutUtils.h"
+#include "nsTextFrame.h"
+#include "nsContainerFrame.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/CheckedInt.h"
+#include "mozilla/ContentIterator.h"
+#include "mozilla/dom/CharacterData.h"
+#include "mozilla/dom/ChildIterator.h"
+#include "mozilla/dom/DOMRect.h"
+#include "mozilla/dom/DOMStringList.h"
+#include "mozilla/dom/DocumentFragment.h"
+#include "mozilla/dom/DocumentType.h"
+#include "mozilla/dom/RangeBinding.h"
+#include "mozilla/dom/Selection.h"
+#include "mozilla/dom/Text.h"
+#include "mozilla/Logging.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/PresShell.h"
+#include "mozilla/RangeUtils.h"
+#include "mozilla/Telemetry.h"
+#include "mozilla/ToString.h"
+#include "mozilla/UniquePtr.h"
+#include "mozilla/Likely.h"
+#include "nsCSSFrameConstructor.h"
+#include "nsStyleStruct.h"
+#include "nsStyleStructInlines.h"
+#include "nsComputedDOMStyle.h"
+#include "mozilla/dom/InspectorFontFace.h"
+
+namespace mozilla {
+extern LazyLogModule sSelectionAPILog;
+extern void LogStackForSelectionAPI();
+
+template <typename SPT, typename SRT, typename EPT, typename ERT>
+static void LogSelectionAPI(const dom::Selection* aSelection,
+                            const char* aFuncName, const char* aArgName1,
+                            const RangeBoundaryBase<SPT, SRT>& aBoundary1,
+                            const char* aArgName2,
+                            const RangeBoundaryBase<EPT, ERT>& aBoundary2,
+                            const char* aArgName3, bool aBoolArg) {
+  if (aBoundary1 == aBoundary2) {
+    MOZ_LOG(sSelectionAPILog, LogLevel::Info,
+            ("%p nsRange::%s(%s=%s=%s, %s=%s)", aSelection, aFuncName,
+             aArgName1, aArgName2, ToString(aBoundary1).c_str(), aArgName3,
+             aBoolArg ? "true" : "false"));
+  } else {
+    MOZ_LOG(
+        sSelectionAPILog, LogLevel::Info,
+        ("%p nsRange::%s(%s=%s, %s=%s, %s=%s)", aSelection, aFuncName,
+         aArgName1, ToString(aBoundary1).c_str(), aArgName2,
+         ToString(aBoundary2).c_str(), aArgName3, aBoolArg ? "true" : "false"));
+  }
+}
+}  // namespace mozilla
+
+using namespace mozilla;
+using namespace mozilla::dom;
+
+template already_AddRefed<nsRange> nsRange::Create(
+    const RangeBoundary& aStartBoundary, const RangeBoundary& aEndBoundary,
+    ErrorResult& aRv);
+template already_AddRefed<nsRange> nsRange::Create(
+    const RangeBoundary& aStartBoundary, const RawRangeBoundary& aEndBoundary,
+    ErrorResult& aRv);
+template already_AddRefed<nsRange> nsRange::Create(
+    const RawRangeBoundary& aStartBoundary, const RangeBoundary& aEndBoundary,
+    ErrorResult& aRv);
+template already_AddRefed<nsRange> nsRange::Create(
+    const RawRangeBoundary& aStartBoundary,
+    const RawRangeBoundary& aEndBoundary, ErrorResult& aRv);
+
+template nsresult nsRange::SetStartAndEnd(const RangeBoundary& aStartBoundary,
+                                          const RangeBoundary& aEndBoundary);
+template nsresult nsRange::SetStartAndEnd(const RangeBoundary& aStartBoundary,
+                                          const RawRangeBoundary& aEndBoundary);
+template nsresult nsRange::SetStartAndEnd(
+    const RawRangeBoundary& aStartBoundary, const RangeBoundary& aEndBoundary);
+template nsresult nsRange::SetStartAndEnd(
+    const RawRangeBoundary& aStartBoundary,
+    const RawRangeBoundary& aEndBoundary);
+
+template void nsRange::DoSetRange(const RangeBoundary& aStartBoundary,
+                                  const RangeBoundary& aEndBoundary,
+                                  nsINode* aRootNode, bool aNotInsertedYet);
+template void nsRange::DoSetRange(const RangeBoundary& aStartBoundary,
+                                  const RawRangeBoundary& aEndBoundary,
+                                  nsINode* aRootNode, bool aNotInsertedYet);
+template void nsRange::DoSetRange(const RawRangeBoundary& aStartBoundary,
+                                  const RangeBoundary& aEndBoundary,
+                                  nsINode* aRootNode, bool aNotInsertedYet);
+template void nsRange::DoSetRange(const RawRangeBoundary& aStartBoundary,
+                                  const RawRangeBoundary& aEndBoundary,
+                                  nsINode* aRootNode, bool aNotInsertedYet);
+
+JSObject* nsRange::WrapObject(JSContext* aCx,
+                              JS::Handle<JSObject*> aGivenProto) {
+  return Range_Binding::Wrap(aCx, this, aGivenProto);
+}
+
+DocGroup* nsRange::GetDocGroup() const {
+  return mOwner ? mOwner->GetDocGroup() : nullptr;
+}
+
+/******************************************************
+ * stack based utility class for managing monitor
+ ******************************************************/
+
+static void InvalidateAllFrames(nsINode* aNode) {
+  MOZ_ASSERT(aNode, "bad arg");
+
+  nsIFrame* frame = nullptr;
+  switch (aNode->NodeType()) {
+    case nsINode::TEXT_NODE:
+    case nsINode::ELEMENT_NODE: {
+      nsIContent* content = static_cast<nsIContent*>(aNode);
+      frame = content->GetPrimaryFrame();
+      break;
+    }
+    case nsINode::DOCUMENT_NODE: {
+      Document* doc = static_cast<Document*>(aNode);
+      PresShell* presShell = doc ? doc->GetPresShell() : nullptr;
+      frame = presShell ? presShell->GetRootFrame() : nullptr;
+      break;
+    }
+  }
+  for (nsIFrame* f = frame; f; f = f->GetNextContinuation()) {
+    f->InvalidateFrameSubtree();
+  }
+}
+
+/******************************************************
+ * constructor/destructor
+ ******************************************************/
+
+nsTArray<RefPtr<nsRange>>* nsRange::sCachedRanges = nullptr;
+
+nsRange::~nsRange() {
+  NS_ASSERTION(!IsInAnySelection(), "deleting nsRange that is in use");
+
+  // we want the side effects (releases and list removals)
+  DoSetRange(RawRangeBoundary(), RawRangeBoundary(), nullptr);
+}
+
+nsRange::nsRange(nsINode* aNode)
+    : AbstractRange(aNode, /* aIsDynamicRange = */ true),
+      mNextStartRef(nullptr),
+      mNextEndRef(nullptr) {
+  // printf("Size of nsRange: %zu\n", sizeof(nsRange));
+
+  static_assert(sizeof(nsRange) <= 240,
+                "nsRange size shouldn't be increased as far as possible");
+}
+
+/* static */
+already_AddRefed<nsRange> nsRange::Create(nsINode* aNode) {
+  MOZ_ASSERT(aNode);
+  if (!sCachedRanges || sCachedRanges->IsEmpty()) {
+    return do_AddRef(new nsRange(aNode));
+  }
+  RefPtr<nsRange> range = sCachedRanges->PopLastElement().forget();
+  range->Init(aNode);
+  return range.forget();
+}
+
+/* static */
+template <typename SPT, typename SRT, typename EPT, typename ERT>
+already_AddRefed<nsRange> nsRange::Create(
+    const RangeBoundaryBase<SPT, SRT>& aStartBoundary,
+    const RangeBoundaryBase<EPT, ERT>& aEndBoundary, ErrorResult& aRv) {
+  // If we fail to initialize the range a lot, nsRange should have a static
+  // initializer since the allocation cost is not cheap in hot path.
+  RefPtr<nsRange> range = nsRange::Create(aStartBoundary.Container());
+  aRv = range->SetStartAndEnd(aStartBoundary, aEndBoundary);
+  if (NS_WARN_IF(aRv.Failed())) {
+    return nullptr;
+  }
+  return range.forget();
+}
+
+/******************************************************
+ * nsISupports
+ ******************************************************/
+
+NS_IMPL_CYCLE_COLLECTING_ADDREF(nsRange)
+NS_IMPL_CYCLE_COLLECTING_RELEASE_WITH_INTERRUPTABLE_LAST_RELEASE(
+    nsRange, DoSetRange(RawRangeBoundary(), RawRangeBoundary(), nullptr),
+    MaybeInterruptLastRelease())
+
+// QueryInterface implementation for nsRange
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(nsRange)
+  NS_INTERFACE_MAP_ENTRY(nsIMutationObserver)
+NS_INTERFACE_MAP_END_INHERITING(AbstractRange)
+
+NS_IMPL_CYCLE_COLLECTION_CLASS(nsRange)
+
+NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(nsRange, AbstractRange)
+  // `Reset()` unlinks `mStart`, `mEnd` and `mRoot`.
+  tmp->Reset();
+NS_IMPL_CYCLE_COLLECTION_UNLINK_END
+
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(nsRange, AbstractRange)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mRoot)
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
+
+NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN_INHERITED(nsRange, AbstractRange)
+NS_IMPL_CYCLE_COLLECTION_TRACE_END
+
+bool nsRange::MaybeInterruptLastRelease() {
+  bool interrupt = AbstractRange::MaybeCacheToReuse(*this);
+  MOZ_ASSERT(!interrupt || IsCleared());
+  return interrupt;
+}
+
+void nsRange::AdjustNextRefsOnCharacterDataSplit(
+    const nsIContent& aContent, const CharacterDataChangeInfo& aInfo) {
+  // If the splitted text node is immediately before a range boundary point
+  // that refers to a child index (i.e. its parent is the boundary container)
+  // then we need to adjust the corresponding boundary to account for the new
+  // text node that will be inserted. However, because the new sibling hasn't
+  // been inserted yet, that would result in an invalid boundary. Therefore,
+  // we store the new child in mNext*Ref to make sure we adjust the boundary
+  // in the next ContentInserted or ContentAppended call.
+  nsINode* parentNode = aContent.GetParentNode();
+  if (parentNode == mEnd.Container()) {
+    if (&aContent == mEnd.Ref()) {
+      MOZ_ASSERT(aInfo.mDetails->mNextSibling);
+      mNextEndRef = aInfo.mDetails->mNextSibling;
+    }
+  }
+
+  if (parentNode == mStart.Container()) {
+    if (&aContent == mStart.Ref()) {
+      MOZ_ASSERT(aInfo.mDetails->mNextSibling);
+      mNextStartRef = aInfo.mDetails->mNextSibling;
+    }
+  }
+}
+
+nsRange::RangeBoundariesAndRoot
+nsRange::DetermineNewRangeBoundariesAndRootOnCharacterDataMerge(
+    nsIContent* aContent, const CharacterDataChangeInfo& aInfo) const {
+  RawRangeBoundary newStart;
+  RawRangeBoundary newEnd;
+  nsINode* newRoot = nullptr;
+
+  // normalize(), aInfo.mDetails->mNextSibling is the merged text node
+  // that will be removed
+  nsIContent* removed = aInfo.mDetails->mNextSibling;
+  if (removed == mStart.Container()) {
+    CheckedUint32 newStartOffset{
+        *mStart.Offset(RangeBoundary::OffsetFilter::kValidOrInvalidOffsets)};
+    newStartOffset += aInfo.mChangeStart;
+
+    // newStartOffset.isValid() isn't checked explicitly here, because
+    // newStartOffset.value() contains an assertion.
+    newStart = {aContent, newStartOffset.value()};
+    if (MOZ_UNLIKELY(removed == mRoot)) {
+      newRoot = RangeUtils::ComputeRootNode(newStart.Container());
+    }
+  }
+  if (removed == mEnd.Container()) {
+    CheckedUint32 newEndOffset{
+        *mEnd.Offset(RangeBoundary::OffsetFilter::kValidOrInvalidOffsets)};
+    newEndOffset += aInfo.mChangeStart;
+
+    // newEndOffset.isValid() isn't checked explicitly here, because
+    // newEndOffset.value() contains an assertion.
+    newEnd = {aContent, newEndOffset.value()};
+    if (MOZ_UNLIKELY(removed == mRoot)) {
+      newRoot = {RangeUtils::ComputeRootNode(newEnd.Container())};
+    }
+  }
+  // When the removed text node's parent is one of our boundary nodes we may
+  // need to adjust the offset to account for the removed node. However,
+  // there will also be a ContentRemoved notification later so the only cases
+  // we need to handle here is when the removed node is the text node after
+  // the boundary.  (The m*Offset > 0 check is an optimization - a boundary
+  // point before the first child is never affected by normalize().)
+  nsINode* parentNode = aContent->GetParentNode();
+  if (parentNode == mStart.Container() &&
+      *mStart.Offset(RangeBoundary::OffsetFilter::kValidOrInvalidOffsets) > 0 &&
+      *mStart.Offset(RangeBoundary::OffsetFilter::kValidOrInvalidOffsets) <
+          parentNode->GetChildCount() &&
+      removed == mStart.GetChildAtOffset()) {
+    newStart = {aContent, aInfo.mChangeStart};
+  }
+  if (parentNode == mEnd.Container() &&
+      *mEnd.Offset(RangeBoundary::OffsetFilter::kValidOrInvalidOffsets) > 0 &&
+      *mEnd.Offset(RangeBoundary::OffsetFilter::kValidOrInvalidOffsets) <
+          parentNode->GetChildCount() &&
+      removed == mEnd.GetChildAtOffset()) {
+    newEnd = {aContent, aInfo.mChangeEnd};
+  }
+
+  return {newStart, newEnd, newRoot};
+}
+
+/******************************************************
+ * nsIMutationObserver implementation
+ ******************************************************/
+void nsRange::CharacterDataChanged(nsIContent* aContent,
+                                   const CharacterDataChangeInfo& aInfo) {
+  MOZ_ASSERT(aContent);
+  MOZ_ASSERT(mIsPositioned);
+  MOZ_ASSERT(!mNextEndRef);
+  MOZ_ASSERT(!mNextStartRef);
+
+  nsINode* newRoot = nullptr;
+  RawRangeBoundary newStart;
+  RawRangeBoundary newEnd;
+
+  if (aInfo.mDetails &&
+      aInfo.mDetails->mType == CharacterDataChangeInfo::Details::eSplit) {
+    AdjustNextRefsOnCharacterDataSplit(*aContent, aInfo);
+  }
+
+  // If the changed node contains our start boundary and the change starts
+  // before the boundary we'll need to adjust the offset.
+  if (aContent == mStart.Container() &&
+      aInfo.mChangeStart <
+          *mStart.Offset(RangeBoundary::OffsetFilter::kValidOrInvalidOffsets)) {
+    if (aInfo.mDetails) {
+      // splitText(), aInfo->mDetails->mNextSibling is the new text node
+      NS_ASSERTION(
+          aInfo.mDetails->mType == CharacterDataChangeInfo::Details::eSplit,
+          "only a split can start before the end");
+      NS_ASSERTION(
+          *mStart.Offset(RangeBoundary::OffsetFilter::kValidOrInvalidOffsets) <=
+              aInfo.mChangeEnd + 1,
+          "mStart.Offset() is beyond the end of this node");
+      const uint32_t newStartOffset =
+          *mStart.Offset(RangeBoundary::OffsetFilter::kValidOrInvalidOffsets) -
+          aInfo.mChangeStart;
+      newStart = {aInfo.mDetails->mNextSibling, newStartOffset};
+      if (MOZ_UNLIKELY(aContent == mRoot)) {
+        newRoot = RangeUtils::ComputeRootNode(newStart.Container());
+      }
+
+      bool isCommonAncestor =
+          IsInAnySelection() && mStart.Container() == mEnd.Container();
+      if (isCommonAncestor) {
+        UnregisterClosestCommonInclusiveAncestor(mStart.Container(), false);
+        RegisterClosestCommonInclusiveAncestor(newStart.Container());
+      }
+      if (mStart.Container()
+              ->IsDescendantOfClosestCommonInclusiveAncestorForRangeInSelection()) {
+        newStart.Container()
+            ->SetDescendantOfClosestCommonInclusiveAncestorForRangeInSelection();
+      }
+    } else {
+      // If boundary is inside changed text, position it before change
+      // else adjust start offset for the change in length.
+      CheckedUint32 newStartOffset{0};
+      if (*mStart.Offset(RangeBoundary::OffsetFilter::kValidOrInvalidOffsets) <=
+          aInfo.mChangeEnd) {
+        newStartOffset = aInfo.mChangeStart;
+      } else {
+        newStartOffset =
+            *mStart.Offset(RangeBoundary::OffsetFilter::kValidOrInvalidOffsets);
+        newStartOffset -= aInfo.LengthOfRemovedText();
+        newStartOffset += aInfo.mReplaceLength;
+      }
+
+      // newStartOffset.isValid() isn't checked explicitly here, because
+      // newStartOffset.value() contains an assertion.
+      newStart = {mStart.Container(), newStartOffset.value()};
+    }
+  }
+
+  // Do the same thing for the end boundary, except for splitText of a node
+  // with no parent then only switch to the new node if the start boundary
+  // did so too (otherwise the range would end up with disconnected nodes).
+  if (aContent == mEnd.Container() &&
+      aInfo.mChangeStart <
+          *mEnd.Offset(RangeBoundary::OffsetFilter::kValidOrInvalidOffsets)) {
+    if (aInfo.mDetails && (aContent->GetParentNode() || newStart.Container())) {
+      // splitText(), aInfo.mDetails->mNextSibling is the new text node
+      NS_ASSERTION(
+          aInfo.mDetails->mType == CharacterDataChangeInfo::Details::eSplit,
+          "only a split can start before the end");
+      MOZ_ASSERT(
+          *mEnd.Offset(RangeBoundary::OffsetFilter::kValidOrInvalidOffsets) <=
+              aInfo.mChangeEnd + 1,
+          "mEnd.Offset() is beyond the end of this node");
+
+      const uint32_t newEndOffset{
+          *mEnd.Offset(RangeBoundary::OffsetFilter::kValidOrInvalidOffsets) -
+          aInfo.mChangeStart};
+      newEnd = {aInfo.mDetails->mNextSibling, newEndOffset};
+
+      bool isCommonAncestor =
+          IsInAnySelection() && mStart.Container() == mEnd.Container();
+      if (isCommonAncestor && !newStart.Container()) {
+        // The split occurs inside the range.
+        UnregisterClosestCommonInclusiveAncestor(mStart.Container(), false);
+        RegisterClosestCommonInclusiveAncestor(
+            mStart.Container()->GetParentNode());
+        newEnd.Container()
+            ->SetDescendantOfClosestCommonInclusiveAncestorForRangeInSelection();
+      } else if (
+          mEnd.Container()
+              ->IsDescendantOfClosestCommonInclusiveAncestorForRangeInSelection()) {
+        newEnd.Container()
+            ->SetDescendantOfClosestCommonInclusiveAncestorForRangeInSelection();
+      }
+    } else {
+      CheckedUint32 newEndOffset{0};
+      if (*mEnd.Offset(RangeBoundary::OffsetFilter::kValidOrInvalidOffsets) <=
+          aInfo.mChangeEnd) {
+        newEndOffset = aInfo.mChangeStart;
+      } else {
+        newEndOffset =
+            *mEnd.Offset(RangeBoundary::OffsetFilter::kValidOrInvalidOffsets);
+        newEndOffset -= aInfo.LengthOfRemovedText();
+        newEndOffset += aInfo.mReplaceLength;
+      }
+
+      // newEndOffset.isValid() isn't checked explicitly here, because
+      // newEndOffset.value() contains an assertion.
+      newEnd = {mEnd.Container(), newEndOffset.value()};
+    }
+  }
+
+  if (aInfo.mDetails &&
+      aInfo.mDetails->mType == CharacterDataChangeInfo::Details::eMerge) {
+    MOZ_ASSERT(!newStart.IsSet());
+    MOZ_ASSERT(!newEnd.IsSet());
+
+    RangeBoundariesAndRoot rangeBoundariesAndRoot =
+        DetermineNewRangeBoundariesAndRootOnCharacterDataMerge(aContent, aInfo);
+
+    newStart = rangeBoundariesAndRoot.mStart;
+    newEnd = rangeBoundariesAndRoot.mEnd;
+    newRoot = rangeBoundariesAndRoot.mRoot;
+  }
+
+  if (newStart.IsSet() || newEnd.IsSet()) {
+    if (!newStart.IsSet()) {
+      newStart.CopyFrom(mStart, RangeBoundaryIsMutationObserved::Yes);
+    }
+    if (!newEnd.IsSet()) {
+      newEnd.CopyFrom(mEnd, RangeBoundaryIsMutationObserved::Yes);
+    }
+    DoSetRange(newStart, newEnd, newRoot ? newRoot : mRoot.get(),
+               !newEnd.Container()->GetParentNode() ||
+                   !newStart.Container()->GetParentNode());
+  } else {
+    nsRange::AssertIfMismatchRootAndRangeBoundaries(
+        mStart, mEnd, mRoot,
+        (mStart.IsSet() && !mStart.Container()->GetParentNode()) ||
+            (mEnd.IsSet() && !mEnd.Container()->GetParentNode()));
+  }
+}
+
+void nsRange::ContentAppended(nsIContent* aFirstNewContent) {
+  MOZ_ASSERT(mIsPositioned);
+
+  nsINode* container = aFirstNewContent->GetParentNode();
+  MOZ_ASSERT(container);
+  if (container->IsMaybeSelected() && IsInAnySelection()) {
+    nsINode* child = aFirstNewContent;
+    while (child) {
+      if (!child
+               ->IsDescendantOfClosestCommonInclusiveAncestorForRangeInSelection()) {
+        MarkDescendants(*child);
+        child
+            ->SetDescendantOfClosestCommonInclusiveAncestorForRangeInSelection();
+      }
+      child = child->GetNextSibling();
+    }
+  }
+
+  if (mNextStartRef || mNextEndRef) {
+    // A splitText has occurred, if any mNext*Ref was set, we need to adjust
+    // the range boundaries.
+    if (mNextStartRef) {
+      mStart = {mStart.Container(), mNextStartRef};
+      MOZ_ASSERT(mNextStartRef == aFirstNewContent);
+      mNextStartRef = nullptr;
+    }
+    if (mNextEndRef) {
+      mEnd = {mEnd.Container(), mNextEndRef};
+      MOZ_ASSERT(mNextEndRef == aFirstNewContent);
+      mNextEndRef = nullptr;
+    }
+    DoSetRange(mStart, mEnd, mRoot, true);
+  } else {
+    nsRange::AssertIfMismatchRootAndRangeBoundaries(mStart, mEnd, mRoot);
+  }
+}
+
+void nsRange::ContentInserted(nsIContent* aChild) {
+  MOZ_ASSERT(mIsPositioned);
+
+  bool updateBoundaries = false;
+  nsINode* container = aChild->GetParentNode();
+  MOZ_ASSERT(container);
+  RawRangeBoundary newStart(mStart, RangeBoundaryIsMutationObserved::Yes);
+  RawRangeBoundary newEnd(mEnd, RangeBoundaryIsMutationObserved::Yes);
+  MOZ_ASSERT(aChild->GetParentNode() == container);
+
+  // Invalidate boundary offsets if a child that may have moved them was
+  // inserted.
+  if (container == mStart.Container()) {
+    newStart.InvalidateOffset();
+    updateBoundaries = true;
+  }
+
+  if (container == mEnd.Container()) {
+    newEnd.InvalidateOffset();
+    updateBoundaries = true;
+  }
+
+  if (container->IsMaybeSelected() &&
+      !aChild
+           ->IsDescendantOfClosestCommonInclusiveAncestorForRangeInSelection()) {
+    MarkDescendants(*aChild);
+    aChild->SetDescendantOfClosestCommonInclusiveAncestorForRangeInSelection();
+  }
+
+  if (mNextStartRef || mNextEndRef) {
+    if (mNextStartRef) {
+      newStart = {mStart.Container(), mNextStartRef};
+      MOZ_ASSERT(mNextStartRef == aChild);
+      mNextStartRef = nullptr;
+    }
+    if (mNextEndRef) {
+      newEnd = {mEnd.Container(), mNextEndRef};
+      MOZ_ASSERT(mNextEndRef == aChild);
+      mNextEndRef = nullptr;
+    }
+
+    updateBoundaries = true;
+  }
+
+  if (updateBoundaries) {
+    DoSetRange(newStart, newEnd, mRoot);
+  } else {
+    nsRange::AssertIfMismatchRootAndRangeBoundaries(mStart, mEnd, mRoot);
+  }
+}
+
+void nsRange::ContentRemoved(nsIContent* aChild, nsIContent* aPreviousSibling) {
+  MOZ_ASSERT(mIsPositioned);
+
+  nsINode* container = aChild->GetParentNode();
+  MOZ_ASSERT(container);
+
+  nsINode* startContainer = mStart.Container();
+  nsINode* endContainer = mEnd.Container();
+
+  RawRangeBoundary newStart;
+  RawRangeBoundary newEnd;
+  Maybe<bool> gravitateStart;
+  bool gravitateEnd;
+
+  // Adjust position if a sibling was removed...
+  if (container == startContainer) {
+    // We're only interested if our boundary reference was removed, otherwise
+    // we can just invalidate the offset.
+    if (aChild == mStart.Ref()) {
+      newStart = {container, aPreviousSibling};
+    } else {
+      newStart.CopyFrom(mStart, RangeBoundaryIsMutationObserved::Yes);
+      newStart.InvalidateOffset();
+    }
+  } else {
+    gravitateStart = Some(startContainer->IsInclusiveDescendantOf(aChild));
+    if (gravitateStart.value()) {
+      newStart = {container, aPreviousSibling};
+    }
+  }
+
+  // Do same thing for end boundry.
+  if (container == endContainer) {
+    if (aChild == mEnd.Ref()) {
+      newEnd = {container, aPreviousSibling};
+    } else {
+      newEnd.CopyFrom(mEnd, RangeBoundaryIsMutationObserved::Yes);
+      newEnd.InvalidateOffset();
+    }
+  } else {
+    if (startContainer == endContainer && gravitateStart.isSome()) {
+      gravitateEnd = gravitateStart.value();
+    } else {
+      gravitateEnd = endContainer->IsInclusiveDescendantOf(aChild);
+    }
+    if (gravitateEnd) {
+      newEnd = {container, aPreviousSibling};
+    }
+  }
+
+  bool newStartIsSet = newStart.IsSet();
+  bool newEndIsSet = newEnd.IsSet();
+  if (newStartIsSet || newEndIsSet) {
+    DoSetRange(newStartIsSet ? newStart : mStart.AsRaw(),
+               newEndIsSet ? newEnd : mEnd.AsRaw(), mRoot);
+  } else {
+    nsRange::AssertIfMismatchRootAndRangeBoundaries(mStart, mEnd, mRoot);
+  }
+
+  MOZ_ASSERT(mStart.Ref() != aChild);
+  MOZ_ASSERT(mEnd.Ref() != aChild);
+
+  if (container->IsMaybeSelected() &&
+      aChild
+          ->IsDescendantOfClosestCommonInclusiveAncestorForRangeInSelection()) {
+    aChild
+        ->ClearDescendantOfClosestCommonInclusiveAncestorForRangeInSelection();
+    UnmarkDescendants(*aChild);
+  }
+}
+
+void nsRange::ParentChainChanged(nsIContent* aContent) {
+  NS_ASSERTION(mRoot == aContent, "Wrong ParentChainChanged notification?");
+  nsINode* newRoot = RangeUtils::ComputeRootNode(mStart.Container());
+  NS_ASSERTION(newRoot, "No valid boundary or root found!");
+  if (newRoot != RangeUtils::ComputeRootNode(mEnd.Container())) {
+    // Sometimes ordering involved in cycle collection can lead to our
+    // start parent and/or end parent being disconnected from our root
+    // without our getting a ContentRemoved notification.
+    // See bug 846096 for more details.
+    NS_ASSERTION(mEnd.Container()->IsInNativeAnonymousSubtree(),
+                 "This special case should happen only with "
+                 "native-anonymous content");
+    // When that happens, bail out and set pointers to null; since we're
+    // in cycle collection and unreachable it shouldn't matter.
+    Reset();
+    return;
+  }
+  // This is safe without holding a strong ref to self as long as the change
+  // of mRoot is the last thing in DoSetRange.
+  DoSetRange(mStart, mEnd, newRoot);
+}
+
+bool nsRange::IsPointComparableToRange(const nsINode& aContainer,
+                                       uint32_t aOffset,
+                                       ErrorResult& aRv) const {
+  // our range is in a good state?
+  if (!mIsPositioned) {
+    aRv.Throw(NS_ERROR_NOT_INITIALIZED);
+    return false;
+  }
+
+  if (!aContainer.IsInclusiveDescendantOf(mRoot)) {
+    // TODO(emilio): Switch to ThrowWrongDocumentError, but IsPointInRange
+    // relies on the error code right now in order to suppress the exception.
+    aRv.Throw(NS_ERROR_DOM_WRONG_DOCUMENT_ERR);
+    return false;
+  }
+
+  auto chromeOnlyAccess = mStart.Container()->ChromeOnlyAccess();
+  NS_ASSERTION(chromeOnlyAccess == mEnd.Container()->ChromeOnlyAccess(),
+               "Start and end of a range must be either both native anonymous "
+               "content or not.");
+  if (aContainer.ChromeOnlyAccess() != chromeOnlyAccess) {
+    aRv.ThrowInvalidNodeTypeError(
+        "Trying to compare restricted with unrestricted nodes");
+    return false;
+  }
+
+  if (aContainer.NodeType() == nsINode::DOCUMENT_TYPE_NODE) {
+    aRv.ThrowInvalidNodeTypeError("Trying to compare with a document");
+    return false;
+  }
+
+  if (aOffset > aContainer.Length()) {
+    aRv.ThrowIndexSizeError("Offset is out of bounds");
+    return false;
+  }
+
+  return true;
+}
+
+bool nsRange::IsPointInRange(const nsINode& aContainer, uint32_t aOffset,
+                             ErrorResult& aRv) const {
+  uint16_t compareResult = ComparePoint(aContainer, aOffset, aRv);
+  // If the node isn't in the range's document, it clearly isn't in the range.
+  if (aRv.ErrorCodeIs(NS_ERROR_DOM_WRONG_DOCUMENT_ERR)) {
+    aRv.SuppressException();
+    return false;
+  }
+
+  return compareResult == 0;
+}
+
+int16_t nsRange::ComparePoint(const nsINode& aContainer, uint32_t aOffset,
+                              ErrorResult& aRv) const {
+  if (!IsPointComparableToRange(aContainer, aOffset, aRv)) {
+    return 0;
+  }
+
+  const RawRangeBoundary point{const_cast<nsINode*>(&aContainer), aOffset};
+
+  MOZ_ASSERT(point.IsSetAndValid());
+
+  if (Maybe<int32_t> order = nsContentUtils::ComparePoints(point, mStart);
+      order && *order <= 0) {
+    return int16_t(*order);
+  }
+  if (Maybe<int32_t> order = nsContentUtils::ComparePoints(mEnd, point);
+      order && *order == -1) {
+    return 1;
+  }
+  return 0;
+}
+
+bool nsRange::IntersectsNode(nsINode& aNode, ErrorResult& aRv) {
+  if (!mIsPositioned) {
+    aRv.Throw(NS_ERROR_NOT_INITIALIZED);
+    return false;
+  }
+
+  nsINode* parent = aNode.GetParentNode();
+  if (!parent) {
+    // |parent| is null, so |node|'s root is |node| itself.
+    return GetRoot() == &aNode;
+  }
+
+  const Maybe<uint32_t> nodeIndex = parent->ComputeIndexOf(&aNode);
+  if (nodeIndex.isNothing()) {
+    return false;
+  }
+
+  if (!IsPointComparableToRange(*parent, *nodeIndex, IgnoreErrors())) {
+    return false;
+  }
+
+  const Maybe<int32_t> startOrder = nsContentUtils::ComparePoints(
+      mStart.Container(),
+      *mStart.Offset(RangeBoundary::OffsetFilter::kValidOffsets), parent,
+      *nodeIndex + 1u);
+  if (startOrder && (*startOrder < 0)) {
+    const Maybe<int32_t> endOrder = nsContentUtils::ComparePoints(
+        parent, *nodeIndex, mEnd.Container(),
+        *mEnd.Offset(RangeBoundary::OffsetFilter::kValidOffsets));
+    return endOrder && (*endOrder < 0);
+  }
+
+  return false;
+}
+
+void nsRange::NotifySelectionListenersAfterRangeSet() {
+  if (mSelections.IsEmpty()) {
+    return;
+  }
+
+  // Our internal code should not move focus with using this instance while
+  // it's calling Selection::NotifySelectionListeners() which may move focus
+  // or calls selection listeners.  So, let's set mCalledByJS to false here
+  // since non-*JS() methods don't set it to false.
+  AutoCalledByJSRestore calledByJSRestorer(*this);
+  mCalledByJS = false;
+
+  // If this instance is not a proper range for selection, we need to remove
+  // this from selections.
+  const Document* const docForSelf =
+      mStart.Container() ? mStart.Container()->GetComposedDoc() : nullptr;
+  const nsFrameSelection* const frameSelection =
+      mSelections[0]->GetFrameSelection();
+  const Document* const docForSelection =
+      frameSelection && frameSelection->GetPresShell()
+          ? frameSelection->GetPresShell()->GetDocument()
+          : nullptr;
+  if (!IsPositioned() || docForSelf != docForSelection) {
+    // XXX Why Selection::RemoveRangeAndUnselectFramesAndNotifyListeners() does
+    // not set whether the caller is JS or not?
+    if (IsPartOfOneSelectionOnly()) {
+      RefPtr<Selection> selection = mSelections[0].get();
+      selection->RemoveRangeAndUnselectFramesAndNotifyListeners(*this,
+                                                                IgnoreErrors());
+    } else {
+      nsTArray<WeakPtr<Selection>> copiedSelections = mSelections.Clone();
+      for (const auto& weakSelection : copiedSelections) {
+        RefPtr<Selection> selection = weakSelection.get();
+        if (MOZ_LIKELY(selection)) {
+          selection->RemoveRangeAndUnselectFramesAndNotifyListeners(
+              *this, IgnoreErrors());
+        }
+      }
+    }
+    // FYI: NotifySelectionListeners() should be called by
+    // RemoveRangeAndUnselectFramesAndNotifyListeners() if it's required.
+    // Therefore, we need to do nothing anymore.
+    return;
+  }
+
+  // Notify all Selections. This may modify the range,
+  // remove it from the selection, or the selection itself may have gone after
+  // the call. Also, new selections may be added.
+  // To ensure that listeners are notified for all *current* selections,
+  // create a copy of the list of selections and use that for iterating. This
+  // way selections can be added or removed safely during iteration.
+  // To save allocation cost, the copy is only created if there is more than
+  // one Selection present  (which will barely ever be the case).
+  if (IsPartOfOneSelectionOnly()) {
+    RefPtr<Selection> selection = mSelections[0].get();
+    selection->NotifySelectionListeners(calledByJSRestorer.SavedValue());
+  } else {
+    nsTArray<WeakPtr<Selection>> copiedSelections = mSelections.Clone();
+    for (const auto& weakSelection : copiedSelections) {
+      RefPtr<Selection> selection = weakSelection.get();
+      if (MOZ_LIKELY(selection)) {
+        selection->NotifySelectionListeners(calledByJSRestorer.SavedValue());
+      }
+    }
+  }
+}
+
+/******************************************************
+ * Private helper routines
+ ******************************************************/
+
+// static
+template <typename SPT, typename SRT, typename EPT, typename ERT>
+void nsRange::AssertIfMismatchRootAndRangeBoundaries(
+    const RangeBoundaryBase<SPT, SRT>& aStartBoundary,
+    const RangeBoundaryBase<EPT, ERT>& aEndBoundary, const nsINode* aRootNode,
+    bool aNotInsertedYet /* = false */) {
+#ifdef DEBUG
+  if (!aRootNode) {
+    MOZ_ASSERT(!aStartBoundary.IsSet());
+    MOZ_ASSERT(!aEndBoundary.IsSet());
+    return;
+  }
+
+  MOZ_ASSERT(aStartBoundary.IsSet());
+  MOZ_ASSERT(aEndBoundary.IsSet());
+  if (!aNotInsertedYet) {
+    // Compute temporary root for given range boundaries.  If a range in native
+    // anonymous subtree is being removed, tempRoot may return the fragment's
+    // root content, but it shouldn't be used for new root node because the node
+    // may be bound to the root element again.
+    nsINode* tempRoot = RangeUtils::ComputeRootNode(aStartBoundary.Container());
+    // The new range should be in the temporary root node at least.
+    MOZ_ASSERT(tempRoot ==
+               RangeUtils::ComputeRootNode(aEndBoundary.Container()));
+    MOZ_ASSERT(aStartBoundary.Container()->IsInclusiveDescendantOf(tempRoot));
+    MOZ_ASSERT(aEndBoundary.Container()->IsInclusiveDescendantOf(tempRoot));
+    // If the new range is not disconnected or not in native anonymous subtree,
+    // the temporary root must be same as the new root node.  Otherwise,
+    // aRootNode should be the parent of root of the NAC (e.g., `<input>` if the
+    // range is in NAC under `<input>`), but tempRoot is now root content node
+    // of the disconnected subtree (e.g., `<div>` element in `<input>` element).
+    const bool tempRootIsDisconnectedNAC =
+        tempRoot->IsInNativeAnonymousSubtree() && !tempRoot->GetParentNode();
+    MOZ_ASSERT_IF(!tempRootIsDisconnectedNAC, tempRoot == aRootNode);
+  }
+  MOZ_ASSERT(aRootNode->IsDocument() || aRootNode->IsAttr() ||
+             aRootNode->IsDocumentFragment() || aRootNode->IsContent());
+#endif  // #ifdef DEBUG
+}
+
+// It's important that all setting of the range start/end points
+// go through this function, which will do all the right voodoo
+// for content notification of range ownership.
+// Calling DoSetRange with either parent argument null will collapse
+// the range to have both endpoints point to the other node
+template <typename SPT, typename SRT, typename EPT, typename ERT>
+void nsRange::DoSetRange(const RangeBoundaryBase<SPT, SRT>& aStartBoundary,
+                         const RangeBoundaryBase<EPT, ERT>& aEndBoundary,
+                         nsINode* aRootNode,
+                         bool aNotInsertedYet /* = false */) {
+  mIsPositioned = aStartBoundary.IsSetAndValid() &&
+                  aEndBoundary.IsSetAndValid() && aRootNode;
+  MOZ_ASSERT_IF(!mIsPositioned, !aStartBoundary.IsSet());
+  MOZ_ASSERT_IF(!mIsPositioned, !aEndBoundary.IsSet());
+  MOZ_ASSERT_IF(!mIsPositioned, !aRootNode);
+
+  nsRange::AssertIfMismatchRootAndRangeBoundaries(aStartBoundary, aEndBoundary,
+                                                  aRootNode, aNotInsertedYet);
+
+  if (mRoot != aRootNode) {
+    if (mRoot) {
+      mRoot->RemoveMutationObserver(this);
+    }
+    if (aRootNode) {
+      aRootNode->AddMutationObserver(this);
+    }
+  }
+  bool checkCommonAncestor =
+      (mStart.Container() != aStartBoundary.Container() ||
+       mEnd.Container() != aEndBoundary.Container()) &&
+      IsInAnySelection() && !aNotInsertedYet;
+
+  // GetClosestCommonInclusiveAncestor is unreliable while we're unlinking
+  // (could return null if our start/end have already been unlinked), so make
+  // sure to not use it here to determine our "old" current ancestor.
+  mStart.CopyFrom(aStartBoundary, RangeBoundaryIsMutationObserved::Yes);
+  mEnd.CopyFrom(aEndBoundary, RangeBoundaryIsMutationObserved::Yes);
+
+  if (checkCommonAncestor) {
+    UpdateCommonAncestorIfNecessary();
+  }
+
+  // This needs to be the last thing this function does, other than notifying
+  // selection listeners. See comment in ParentChainChanged.
+  if (mRoot != aRootNode) {
+    mRoot = aRootNode;
+  }
+
+  // Notify any selection listeners. This has to occur last because otherwise
+  // the world could be observed by a selection listener while the range was in
+  // an invalid state. So we run it off of a script runner to ensure it runs
+  // after the mutation observers have finished running.
+  if (!mSelections.IsEmpty()) {
+    if (MOZ_LOG_TEST(sSelectionAPILog, LogLevel::Info)) {
+      for (const auto& selection : mSelections) {
+        if (selection && selection->Type() == SelectionType::eNormal) {
+          LogSelectionAPI(selection, __FUNCTION__, "aStartBoundary",
+                          aStartBoundary, "aEndBoundary", aEndBoundary,
+                          "aNotInsertedYet", aNotInsertedYet);
+          LogStackForSelectionAPI();
+        }
+      }
+    }
+    nsContentUtils::AddScriptRunner(
+        NewRunnableMethod("NotifySelectionListenersAfterRangeSet", this,
+                          &nsRange::NotifySelectionListenersAfterRangeSet));
+  }
+}
+
+void nsRange::Reset() {
+  DoSetRange(RawRangeBoundary(), RawRangeBoundary(), nullptr);
+}
+
+/******************************************************
+ * public functionality
+ ******************************************************/
+
+void nsRange::SetStartJS(nsINode& aNode, uint32_t aOffset, ErrorResult& aErr) {
+  AutoCalledByJSRestore calledByJSRestorer(*this);
+  mCalledByJS = true;
+  SetStart(aNode, aOffset, aErr);
+}
+
+bool nsRange::CanAccess(const nsINode& aNode) const {
+  if (nsContentUtils::LegacyIsCallerNativeCode()) {
+    return true;
+  }
+  return nsContentUtils::CanCallerAccess(&aNode);
+}
+
+void nsRange::SetStart(nsINode& aNode, uint32_t aOffset, ErrorResult& aRv) {
+  if (!CanAccess(aNode)) {
+    aRv.Throw(NS_ERROR_DOM_SECURITY_ERR);
+    return;
+  }
+
+  AutoInvalidateSelection atEndOfBlock(this);
+  SetStart(RawRangeBoundary(&aNode, aOffset), aRv);
+}
+
+void nsRange::SetStart(const RawRangeBoundary& aPoint, ErrorResult& aRv) {
+  nsINode* newRoot = RangeUtils::ComputeRootNode(aPoint.Container());
+  if (!newRoot) {
+    aRv.Throw(NS_ERROR_DOM_INVALID_NODE_TYPE_ERR);
+    return;
+  }
+
+  if (!aPoint.IsSetAndValid()) {
+    aRv.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
+    return;
+  }
+
+  // Collapse if not positioned yet, if positioned in another doc or
+  // if the new start is after end.
+  const bool collapse = [&]() {
+    if (!mIsPositioned || (newRoot != mRoot)) {
+      return true;
+    }
+
+    const Maybe<int32_t> order = nsContentUtils::ComparePoints(aPoint, mEnd);
+    if (order) {
+      return *order == 1;
+    }
+
+    MOZ_ASSERT_UNREACHABLE();
+    return true;
+  }();
+
+  if (collapse) {
+    DoSetRange(aPoint, aPoint, newRoot);
+    return;
+  }
+
+  DoSetRange(aPoint, mEnd, mRoot);
+}
+
+void nsRange::SetStartBeforeJS(nsINode& aNode, ErrorResult& aErr) {
+  AutoCalledByJSRestore calledByJSRestorer(*this);
+  mCalledByJS = true;
+  SetStartBefore(aNode, aErr);
+}
+
+void nsRange::SetStartBefore(nsINode& aNode, ErrorResult& aRv) {
+  if (!CanAccess(aNode)) {
+    aRv.Throw(NS_ERROR_DOM_SECURITY_ERR);
+    return;
+  }
+
+  AutoInvalidateSelection atEndOfBlock(this);
+  // If the node is being removed from its parent, GetRawRangeBoundaryBefore()
+  // returns unset instance.  Then, SetStart() will throw
+  // NS_ERROR_DOM_INVALID_NODE_TYPE_ERR.
+  SetStart(RangeUtils::GetRawRangeBoundaryBefore(&aNode), aRv);
+}
+
+void nsRange::SetStartAfterJS(nsINode& aNode, ErrorResult& aErr) {
+  AutoCalledByJSRestore calledByJSRestorer(*this);
+  mCalledByJS = true;
+  SetStartAfter(aNode, aErr);
+}
+
+void nsRange::SetStartAfter(nsINode& aNode, ErrorResult& aRv) {
+  if (!CanAccess(aNode)) {
+    aRv.Throw(NS_ERROR_DOM_SECURITY_ERR);
+    return;
+  }
+
+  AutoInvalidateSelection atEndOfBlock(this);
+  // If the node is being removed from its parent, GetRawRangeBoundaryAfter()
+  // returns unset instance.  Then, SetStart() will throw
+  // NS_ERROR_DOM_INVALID_NODE_TYPE_ERR.
+  SetStart(RangeUtils::GetRawRangeBoundaryAfter(&aNode), aRv);
+}
+
+void nsRange::SetEndJS(nsINode& aNode, uint32_t aOffset, ErrorResult& aErr) {
+  AutoCalledByJSRestore calledByJSRestorer(*this);
+  mCalledByJS = true;
+  SetEnd(aNode, aOffset, aErr);
+}
+
+void nsRange::SetEnd(nsINode& aNode, uint32_t aOffset, ErrorResult& aRv) {
+  if (!CanAccess(aNode)) {
+    aRv.Throw(NS_ERROR_DOM_SECURITY_ERR);
+    return;
+  }
+  AutoInvalidateSelection atEndOfBlock(this);
+  SetEnd(RawRangeBoundary(&aNode, aOffset), aRv);
+}
+
+void nsRange::SetEnd(const RawRangeBoundary& aPoint, ErrorResult& aRv) {
+  nsINode* newRoot = RangeUtils::ComputeRootNode(aPoint.Container());
+  if (!newRoot) {
+    aRv.Throw(NS_ERROR_DOM_INVALID_NODE_TYPE_ERR);
+    return;
+  }
+
+  if (!aPoint.IsSetAndValid()) {
+    aRv.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
+    return;
+  }
+
+  // Collapse if not positioned yet, if positioned in another doc or
+  // if the new end is before start.
+  const bool collapse = [&]() {
+    if (!mIsPositioned || (newRoot != mRoot)) {
+      return true;
+    }
+
+    const Maybe<int32_t> order = nsContentUtils::ComparePoints(mStart, aPoint);
+    if (order) {
+      return *order == 1;
+    }
+
+    MOZ_ASSERT_UNREACHABLE();
+    return true;
+  }();
+
+  if (collapse) {
+    DoSetRange(aPoint, aPoint, newRoot);
+    return;
+  }
+
+  DoSetRange(mStart, aPoint, mRoot);
+}
+
+void nsRange::SelectNodesInContainer(nsINode* aContainer,
+                                     nsIContent* aStartContent,
+                                     nsIContent* aEndContent) {
+  MOZ_ASSERT(aContainer);
+  MOZ_ASSERT(aContainer->ComputeIndexOf(aStartContent).valueOr(0) <=
+             aContainer->ComputeIndexOf(aEndContent).valueOr(0));
+  MOZ_ASSERT(aStartContent &&
+             aContainer->ComputeIndexOf(aStartContent).isSome());
+  MOZ_ASSERT(aEndContent && aContainer->ComputeIndexOf(aEndContent).isSome());
+
+  nsINode* newRoot = RangeUtils::ComputeRootNode(aContainer);
+  MOZ_ASSERT(newRoot);
+  if (!newRoot) {
+    return;
+  }
+
+  RawRangeBoundary start(aContainer, aStartContent->GetPreviousSibling());
+  RawRangeBoundary end(aContainer, aEndContent);
+  DoSetRange(start, end, newRoot);
+}
+
+void nsRange::SetEndBeforeJS(nsINode& aNode, ErrorResult& aErr) {
+  AutoCalledByJSRestore calledByJSRestorer(*this);
+  mCalledByJS = true;
+  SetEndBefore(aNode, aErr);
+}
+
+void nsRange::SetEndBefore(nsINode& aNode, ErrorResult& aRv) {
+  if (!CanAccess(aNode)) {
+    aRv.Throw(NS_ERROR_DOM_SECURITY_ERR);
+    return;
+  }
+
+  AutoInvalidateSelection atEndOfBlock(this);
+  // If the node is being removed from its parent, GetRawRangeBoundaryBefore()
+  // returns unset instance.  Then, SetEnd() will throw
+  // NS_ERROR_DOM_INVALID_NODE_TYPE_ERR.
+  SetEnd(RangeUtils::GetRawRangeBoundaryBefore(&aNode), aRv);
+}
+
+void nsRange::SetEndAfterJS(nsINode& aNode, ErrorResult& aErr) {
+  AutoCalledByJSRestore calledByJSRestorer(*this);
+  mCalledByJS = true;
+  SetEndAfter(aNode, aErr);
+}
+
+void nsRange::SetEndAfter(nsINode& aNode, ErrorResult& aRv) {
+  if (!CanAccess(aNode)) {
+    aRv.Throw(NS_ERROR_DOM_SECURITY_ERR);
+    return;
+  }
+
+  AutoInvalidateSelection atEndOfBlock(this);
+  // If the node is being removed from its parent, GetRawRangeBoundaryAfter()
+  // returns unset instance.  Then, SetEnd() will throw
+  // NS_ERROR_DOM_INVALID_NODE_TYPE_ERR.
+  SetEnd(RangeUtils::GetRawRangeBoundaryAfter(&aNode), aRv);
+}
+
+void nsRange::Collapse(bool aToStart) {
+  if (!mIsPositioned) return;
+
+  AutoInvalidateSelection atEndOfBlock(this);
+  if (aToStart) {
+    DoSetRange(mStart, mStart, mRoot);
+  } else {
+    DoSetRange(mEnd, mEnd, mRoot);
+  }
+}
+
+void nsRange::CollapseJS(bool aToStart) {
+  AutoCalledByJSRestore calledByJSRestorer(*this);
+  mCalledByJS = true;
+  Collapse(aToStart);
+}
+
+void nsRange::SelectNodeJS(nsINode& aNode, ErrorResult& aErr) {
+  AutoCalledByJSRestore calledByJSRestorer(*this);
+  mCalledByJS = true;
+  SelectNode(aNode, aErr);
+}
+
+void nsRange::SelectNode(nsINode& aNode, ErrorResult& aRv) {
+  if (!CanAccess(aNode)) {
+    aRv.Throw(NS_ERROR_DOM_SECURITY_ERR);
+    return;
+  }
+
+  nsINode* container = aNode.GetParentNode();
+  nsINode* newRoot = RangeUtils::ComputeRootNode(container);
+  if (!newRoot) {
+    aRv.Throw(NS_ERROR_DOM_INVALID_NODE_TYPE_ERR);
+    return;
+  }
+
+  const Maybe<uint32_t> index = container->ComputeIndexOf(&aNode);
+  // MOZ_ASSERT(index.isSome());
+  // We need to compute the index here unfortunately, because, while we have
+  // support for XBL, |container| may be the node's binding parent without
+  // actually containing it.
+  if (MOZ_UNLIKELY(NS_WARN_IF(index.isNothing()))) {
+    aRv.Throw(NS_ERROR_DOM_INVALID_NODE_TYPE_ERR);
+    return;
+  }
+
+  AutoInvalidateSelection atEndOfBlock(this);
+  DoSetRange(RawRangeBoundary{container, *index},
+             RawRangeBoundary{container, *index + 1u}, newRoot);
+}
+
+void nsRange::SelectNodeContentsJS(nsINode& aNode, ErrorResult& aErr) {
+  AutoCalledByJSRestore calledByJSRestorer(*this);
+  mCalledByJS = true;
+  SelectNodeContents(aNode, aErr);
+}
+
+void nsRange::SelectNodeContents(nsINode& aNode, ErrorResult& aRv) {
+  if (!CanAccess(aNode)) {
+    aRv.Throw(NS_ERROR_DOM_SECURITY_ERR);
+    return;
+  }
+
+  nsINode* newRoot = RangeUtils::ComputeRootNode(&aNode);
+  if (!newRoot) {
+    aRv.Throw(NS_ERROR_DOM_INVALID_NODE_TYPE_ERR);
+    return;
+  }
+
+  AutoInvalidateSelection atEndOfBlock(this);
+  DoSetRange(RawRangeBoundary(&aNode, 0u),
+             RawRangeBoundary(&aNode, aNode.Length()), newRoot);
+}
+
+// The Subtree Content Iterator only returns subtrees that are
+// completely within a given range. It doesn't return a CharacterData
+// node that contains either the start or end point of the range.,
+// nor does it return element nodes when nothing in the element is selected.
+// We need an iterator that will also include these start/end points
+// so that our methods/algorithms aren't cluttered with special
+// case code that tries to include these points while iterating.
+//
+// The RangeSubtreeIterator class mimics the ContentSubtreeIterator
+// methods we need, so should the Content Iterator support the
+// start/end points in the future, we can switchover relatively
+// easy.
+
+class MOZ_STACK_CLASS RangeSubtreeIterator {
+ private:
+  enum RangeSubtreeIterState { eDone = 0, eUseStart, eUseIterator, eUseEnd };
+
+  Maybe<ContentSubtreeIterator> mSubtreeIter;
+  RangeSubtreeIterState mIterState;
+
+  nsCOMPtr<nsINode> mStart;
+  nsCOMPtr<nsINode> mEnd;
+
+ public:
+  RangeSubtreeIterator() : mIterState(eDone) {}
+  ~RangeSubtreeIterator() = default;
+
+  nsresult Init(nsRange* aRange);
+  already_AddRefed<nsINode> GetCurrentNode();
+  void First();
+  void Last();
+  void Next();
+  void Prev();
+
+  bool IsDone() { return mIterState == eDone; }
+};
+
+nsresult RangeSubtreeIterator::Init(nsRange* aRange) {
+  mIterState = eDone;
+  if (aRange->Collapsed()) {
+    return NS_OK;
+  }
+
+  // Grab the start point of the range and QI it to
+  // a CharacterData pointer. If it is CharacterData store
+  // a pointer to the node.
+
+  if (!aRange->IsPositioned()) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsINode* node = aRange->GetStartContainer();
+  if (NS_WARN_IF(!node)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  if (node->IsCharacterData() ||
+      (node->IsElement() &&
+       node->AsElement()->GetChildCount() == aRange->StartOffset())) {
+    mStart = node;
+  }
+
+  // Grab the end point of the range and QI it to
+  // a CharacterData pointer. If it is CharacterData store
+  // a pointer to the node.
+
+  node = aRange->GetEndContainer();
+  if (NS_WARN_IF(!node)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  if (node->IsCharacterData() ||
+      (node->IsElement() && aRange->EndOffset() == 0)) {
+    mEnd = node;
+  }
+
+  if (mStart && mStart == mEnd) {
+    // The range starts and stops in the same CharacterData
+    // node. Null out the end pointer so we only visit the
+    // node once!
+
+    mEnd = nullptr;
+  } else {
+    // Now create a Content Subtree Iterator to be used
+    // for the subtrees between the end points!
+
+    mSubtreeIter.emplace();
+
+    nsresult res = mSubtreeIter->Init(aRange);
+    if (NS_FAILED(res)) return res;
+
+    if (mSubtreeIter->IsDone()) {
+      // The subtree iterator thinks there's nothing
+      // to iterate over, so just free it up so we
+      // don't accidentally call into it.
+
+      mSubtreeIter.reset();
+    }
+  }
+
+  // Initialize the iterator by calling First().
+  // Note that we are ignoring the return value on purpose!
+
+  First();
+
+  return NS_OK;
+}
+
+already_AddRefed<nsINode> RangeSubtreeIterator::GetCurrentNode() {
+  nsCOMPtr<nsINode> node;
+
+  if (mIterState == eUseStart && mStart) {
+    node = mStart;
+  } else if (mIterState == eUseEnd && mEnd) {
+    node = mEnd;
+  } else if (mIterState == eUseIterator && mSubtreeIter) {
+    node = mSubtreeIter->GetCurrentNode();
+  }
+
+  return node.forget();
+}
+
+void RangeSubtreeIterator::First() {
+  if (mStart)
+    mIterState = eUseStart;
+  else if (mSubtreeIter) {
+    mSubtreeIter->First();
+
+    mIterState = eUseIterator;
+  } else if (mEnd)
+    mIterState = eUseEnd;
+  else
+    mIterState = eDone;
+}
+
+void RangeSubtreeIterator::Last() {
+  if (mEnd)
+    mIterState = eUseEnd;
+  else if (mSubtreeIter) {
+    mSubtreeIter->Last();
+
+    mIterState = eUseIterator;
+  } else if (mStart)
+    mIterState = eUseStart;
+  else
+    mIterState = eDone;
+}
+
+void RangeSubtreeIterator::Next() {
+  if (mIterState == eUseStart) {
+    if (mSubtreeIter) {
+      mSubtreeIter->First();
+
+      mIterState = eUseIterator;
+    } else if (mEnd)
+      mIterState = eUseEnd;
+    else
+      mIterState = eDone;
+  } else if (mIterState == eUseIterator) {
+    mSubtreeIter->Next();
+
+    if (mSubtreeIter->IsDone()) {
+      if (mEnd)
+        mIterState = eUseEnd;
+      else
+        mIterState = eDone;
+    }
+  } else
+    mIterState = eDone;
+}
+
+void RangeSubtreeIterator::Prev() {
+  if (mIterState == eUseEnd) {
+    if (mSubtreeIter) {
+      mSubtreeIter->Last();
+
+      mIterState = eUseIterator;
+    } else if (mStart)
+      mIterState = eUseStart;
+    else
+      mIterState = eDone;
+  } else if (mIterState == eUseIterator) {
+    mSubtreeIter->Prev();
+
+    if (mSubtreeIter->IsDone()) {
+      if (mStart)
+        mIterState = eUseStart;
+      else
+        mIterState = eDone;
+    }
+  } else
+    mIterState = eDone;
+}
+
+// CollapseRangeAfterDelete() is a utility method that is used by
+// DeleteContents() and ExtractContents() to collapse the range
+// in the correct place, under the range's root container (the
+// range end points common container) as outlined by the Range spec:
+//
+// http://www.w3.org/TR/2000/REC-DOM-Level-2-Traversal-Range-20001113/ranges.html
+// The assumption made by this method is that the delete or extract
+// has been done already, and left the range in a state where there is
+// no content between the 2 end points.
+
+static nsresult CollapseRangeAfterDelete(nsRange* aRange) {
+  NS_ENSURE_ARG_POINTER(aRange);
+
+  // Check if range gravity took care of collapsing the range for us!
+  if (aRange->Collapsed()) {
+    // aRange is collapsed so there's nothing for us to do.
+    //
+    // There are 2 possible scenarios here:
+    //
+    // 1. aRange could've been collapsed prior to the delete/extract,
+    //    which would've resulted in nothing being removed, so aRange
+    //    is already where it should be.
+    //
+    // 2. Prior to the delete/extract, aRange's start and end were in
+    //    the same container which would mean everything between them
+    //    was removed, causing range gravity to collapse the range.
+
+    return NS_OK;
+  }
+
+  // aRange isn't collapsed so figure out the appropriate place to collapse!
+  // First get both end points and their common ancestor.
+
+  if (!aRange->IsPositioned()) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+
+  nsCOMPtr<nsINode> commonAncestor =
+      aRange->GetClosestCommonInclusiveAncestor();
+
+  nsCOMPtr<nsINode> startContainer = aRange->GetStartContainer();
+  nsCOMPtr<nsINode> endContainer = aRange->GetEndContainer();
+
+  // Collapse to one of the end points if they are already in the
+  // commonAncestor. This should work ok since this method is called
+  // immediately after a delete or extract that leaves no content
+  // between the 2 end points!
+
+  if (startContainer == commonAncestor) {
+    aRange->Collapse(true);
+    return NS_OK;
+  }
+  if (endContainer == commonAncestor) {
+    aRange->Collapse(false);
+    return NS_OK;
+  }
+
+  // End points are at differing levels. We want to collapse to the
+  // point that is between the 2 subtrees that contain each point,
+  // under the common ancestor.
+
+  nsCOMPtr<nsINode> nodeToSelect(startContainer);
+
+  while (nodeToSelect) {
+    nsCOMPtr<nsINode> parent = nodeToSelect->GetParentNode();
+    if (parent == commonAncestor) break;  // We found the nodeToSelect!
+
+    nodeToSelect = parent;
+  }
+
+  if (!nodeToSelect) return NS_ERROR_FAILURE;  // This should never happen!
+
+  ErrorResult error;
+  aRange->SelectNode(*nodeToSelect, error);
+  if (error.Failed()) {
+    return error.StealNSResult();
+  }
+
+  aRange->Collapse(false);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+PrependChild(nsINode* aContainer, nsINode* aChild) {
+  nsCOMPtr<nsINode> first = aContainer->GetFirstChild();
+  ErrorResult rv;
+  aContainer->InsertBefore(*aChild, first, rv);
+  return rv.StealNSResult();
+}
+
+// Helper function for CutContents, making sure that the current node wasn't
+// removed by mutation events (bug 766426)
+static bool ValidateCurrentNode(nsRange* aRange, RangeSubtreeIterator& aIter) {
+  bool before, after;
+  nsCOMPtr<nsINode> node = aIter.GetCurrentNode();
+  if (!node) {
+    // We don't have to worry that the node was removed if it doesn't exist,
+    // e.g., the iterator is done.
+    return true;
+  }
+
+  nsresult rv = RangeUtils::CompareNodeToRange(node, aRange, &before, &after);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return false;
+  }
+
+  if (before || after) {
+    if (node->IsCharacterData()) {
+      // If we're dealing with the start/end container which is a character
+      // node, pretend that the node is in the range.
+      if (before && node == aRange->GetStartContainer()) {
+        before = false;
+      }
+      if (after && node == aRange->GetEndContainer()) {
+        after = false;
+      }
+    }
+  }
+
+  return !before && !after;
+}
+
+void nsRange::CutContents(DocumentFragment** aFragment, ErrorResult& aRv) {
+  if (aFragment) {
+    *aFragment = nullptr;
+  }
+
+  if (!CanAccess(*mStart.Container()) || !CanAccess(*mEnd.Container())) {
+    aRv.Throw(NS_ERROR_DOM_SECURITY_ERR);
+    return;
+  }
+
+  nsCOMPtr<Document> doc = mStart.Container()->OwnerDoc();
+
+  nsCOMPtr<nsINode> commonAncestor = GetCommonAncestorContainer(aRv);
+  if (aRv.Failed()) {
+    return;
+  }
+
+  // If aFragment isn't null, create a temporary fragment to hold our return.
+  RefPtr<DocumentFragment> retval;
+  if (aFragment) {
+    retval =
+        new (doc->NodeInfoManager()) DocumentFragment(doc->NodeInfoManager());
+  }
+  nsCOMPtr<nsINode> commonCloneAncestor = retval.get();
+
+  // Batch possible DOMSubtreeModified events.
+  mozAutoSubtreeModified subtree(mRoot ? mRoot->OwnerDoc() : nullptr, nullptr);
+
+  // Save the range end points locally to avoid interference
+  // of Range gravity during our edits!
+
+  nsCOMPtr<nsINode> startContainer = mStart.Container();
+  // `GetCommonAncestorContainer()` above ensures the range is positioned, hence
+  // there have to be valid offsets.
+  uint32_t startOffset =
+      *mStart.Offset(RangeBoundary::OffsetFilter::kValidOffsets);
+  nsCOMPtr<nsINode> endContainer = mEnd.Container();
+  uint32_t endOffset = *mEnd.Offset(RangeBoundary::OffsetFilter::kValidOffsets);
+
+  if (retval) {
+    // For extractContents(), abort early if there's a doctype (bug 719533).
+    // This can happen only if the common ancestor is a document, in which case
+    // we just need to find its doctype child and check if that's in the range.
+    nsCOMPtr<Document> commonAncestorDocument =
+        do_QueryInterface(commonAncestor);
+    if (commonAncestorDocument) {
+      RefPtr<DocumentType> doctype = commonAncestorDocument->GetDoctype();
+
+      // `GetCommonAncestorContainer()` above ensured the range is positioned.
+      // Hence, start and end are both set and valid. If available, `doctype`
+      // has a common ancestor with start and end, hence both have to be
+      // comparable to it.
+      if (doctype &&
+          *nsContentUtils::ComparePoints(startContainer, startOffset, doctype,
+                                         0) < 0 &&
+          *nsContentUtils::ComparePoints(doctype, 0, endContainer, endOffset) <
+              0) {
+        aRv.ThrowHierarchyRequestError("Start or end position isn't valid.");
+        return;
+      }
+    }
+  }
+
+  // Create and initialize a subtree iterator that will give
+  // us all the subtrees within the range.
+
+  RangeSubtreeIterator iter;
+
+  aRv = iter.Init(this);
+  if (aRv.Failed()) {
+    return;
+  }
+
+  if (iter.IsDone()) {
+    // There's nothing for us to delete.
+    aRv = CollapseRangeAfterDelete(this);
+    if (!aRv.Failed() && aFragment) {
+      retval.forget(aFragment);
+    }
+    return;
+  }
+
+  iter.First();
+
+  bool handled = false;
+
+  // With the exception of text nodes that contain one of the range
+  // end points, the subtree iterator should only give us back subtrees
+  // that are completely contained between the range's end points.
+
+  while (!iter.IsDone()) {
+    nsCOMPtr<nsINode> nodeToResult;
+    nsCOMPtr<nsINode> node = iter.GetCurrentNode();
+
+    // Before we delete anything, advance the iterator to the next node that's
+    // not a descendant of this one.  XXX It's a bit silly to iterate through
+    // the descendants only to throw them out, we should use an iterator that
+    // skips the descendants to begin with.
+
+    iter.Next();
+    nsCOMPtr<nsINode> nextNode = iter.GetCurrentNode();
+    while (nextNode && nextNode->IsInclusiveDescendantOf(node)) {
+      iter.Next();
+      nextNode = iter.GetCurrentNode();
+    }
+
+    handled = false;
+
+    // If it's CharacterData, make sure we might need to delete
+    // part of the data, instead of removing the whole node.
+    //
+    // XXX_kin: We need to also handle ProcessingInstruction
+    // XXX_kin: according to the spec.
+
+    if (auto charData = CharacterData::FromNode(node)) {
+      uint32_t dataLength = 0;
+
+      if (node == startContainer) {
+        if (node == endContainer) {
+          // This range is completely contained within a single text node.
+          // Delete or extract the data between startOffset and endOffset.
+
+          if (endOffset > startOffset) {
+            if (retval) {
+              nsAutoString cutValue;
+              charData->SubstringData(startOffset, endOffset - startOffset,
+                                      cutValue, aRv);
+              if (NS_WARN_IF(aRv.Failed())) {
+                return;
+              }
+              nsCOMPtr<nsINode> clone = node->CloneNode(false, aRv);
+              if (NS_WARN_IF(aRv.Failed())) {
+                return;
+              }
+              clone->SetNodeValue(cutValue, aRv);
+              if (NS_WARN_IF(aRv.Failed())) {
+                return;
+              }
+              nodeToResult = clone;
+            }
+
+            nsMutationGuard guard;
+            charData->DeleteData(startOffset, endOffset - startOffset, aRv);
+            if (NS_WARN_IF(aRv.Failed())) {
+              return;
+            }
+            if (guard.Mutated(0) && !ValidateCurrentNode(this, iter)) {
+              aRv.Throw(NS_ERROR_UNEXPECTED);
+              return;
+            }
+          }
+
+          handled = true;
+        } else {
+          // Delete or extract everything after startOffset.
+
+          dataLength = charData->Length();
+
+          if (dataLength >= startOffset) {
+            if (retval) {
+              nsAutoString cutValue;
+              charData->SubstringData(startOffset, dataLength, cutValue, aRv);
+              if (NS_WARN_IF(aRv.Failed())) {
+                return;
+              }
+              nsCOMPtr<nsINode> clone = node->CloneNode(false, aRv);
+              if (NS_WARN_IF(aRv.Failed())) {
+                return;
+              }
+              clone->SetNodeValue(cutValue, aRv);
+              if (NS_WARN_IF(aRv.Failed())) {
+                return;
+              }
+              nodeToResult = clone;
+            }
+
+            nsMutationGuard guard;
+            charData->DeleteData(startOffset, dataLength, aRv);
+            if (NS_WARN_IF(aRv.Failed())) {
+              return;
+            }
+            if (guard.Mutated(0) && !ValidateCurrentNode(this, iter)) {
+              aRv.Throw(NS_ERROR_UNEXPECTED);
+              return;
+            }
+          }
+
+          handled = true;
+        }
+      } else if (node == endContainer) {
+        // Delete or extract everything before endOffset.
+        if (retval) {
+          nsAutoString cutValue;
+          charData->SubstringData(0, endOffset, cutValue, aRv);
+          if (NS_WARN_IF(aRv.Failed())) {
+            return;
+          }
+          nsCOMPtr<nsINode> clone = node->CloneNode(false, aRv);
+          if (NS_WARN_IF(aRv.Failed())) {
+            return;
+          }
+          clone->SetNodeValue(cutValue, aRv);
+          if (NS_WARN_IF(aRv.Failed())) {
+            return;
+          }
+          nodeToResult = clone;
+        }
+
+        nsMutationGuard guard;
+        charData->DeleteData(0, endOffset, aRv);
+        if (NS_WARN_IF(aRv.Failed())) {
+          return;
+        }
+        if (guard.Mutated(0) && !ValidateCurrentNode(this, iter)) {
+          aRv.Throw(NS_ERROR_UNEXPECTED);
+          return;
+        }
+        handled = true;
+      }
+    }
+
+    if (!handled && (node == endContainer || node == startContainer)) {
+      if (node && node->IsElement() &&
+          ((node == endContainer && endOffset == 0) ||
+           (node == startContainer &&
+            node->AsElement()->GetChildCount() == startOffset))) {
+        if (retval) {
+          nodeToResult = node->CloneNode(false, aRv);
+          if (aRv.Failed()) {
+            return;
+          }
+        }
+        handled = true;
+      }
+    }
+
+    if (!handled) {
+      // node was not handled above, so it must be completely contained
+      // within the range. Just remove it from the tree!
+      nodeToResult = node;
+    }
+
+    uint32_t parentCount = 0;
+    // Set the result to document fragment if we have 'retval'.
+    if (retval) {
+      nsCOMPtr<nsINode> oldCommonAncestor = commonAncestor;
+      if (!iter.IsDone()) {
+        // Setup the parameters for the next iteration of the loop.
+        if (!nextNode) {
+          aRv.Throw(NS_ERROR_UNEXPECTED);
+          return;
+        }
+
+        // Get node's and nextNode's common parent. Do this before moving
+        // nodes from original DOM to result fragment.
+        commonAncestor =
+            nsContentUtils::GetClosestCommonInclusiveAncestor(node, nextNode);
+        if (!commonAncestor) {
+          aRv.Throw(NS_ERROR_UNEXPECTED);
+          return;
+        }
+
+        nsCOMPtr<nsINode> parentCounterNode = node;
+        while (parentCounterNode && parentCounterNode != commonAncestor) {
+          ++parentCount;
+          parentCounterNode = parentCounterNode->GetParentNode();
+          if (!parentCounterNode) {
+            aRv.Throw(NS_ERROR_UNEXPECTED);
+            return;
+          }
+        }
+      }
+
+      // Clone the parent hierarchy between commonAncestor and node.
+      nsCOMPtr<nsINode> closestAncestor, farthestAncestor;
+      aRv = CloneParentsBetween(oldCommonAncestor, node,
+                                getter_AddRefs(closestAncestor),
+                                getter_AddRefs(farthestAncestor));
+      if (aRv.Failed()) {
+        return;
+      }
+
+      if (farthestAncestor) {
+        commonCloneAncestor->AppendChild(*farthestAncestor, aRv);
+        if (NS_WARN_IF(aRv.Failed())) {
+          return;
+        }
+      }
+
+      nsMutationGuard guard;
+      nsCOMPtr<nsINode> parent = nodeToResult->GetParentNode();
+      if (closestAncestor) {
+        closestAncestor->AppendChild(*nodeToResult, aRv);
+      } else {
+        commonCloneAncestor->AppendChild(*nodeToResult, aRv);
+      }
+      if (NS_WARN_IF(aRv.Failed())) {
+        return;
+      }
+      if (guard.Mutated(parent ? 2 : 1) && !ValidateCurrentNode(this, iter)) {
+        aRv.Throw(NS_ERROR_UNEXPECTED);
+        return;
+      }
+    } else if (nodeToResult) {
+      nsMutationGuard guard;
+      nsCOMPtr<nsINode> node = nodeToResult;
+      nsCOMPtr<nsINode> parent = node->GetParentNode();
+      if (parent) {
+        parent->RemoveChild(*node, aRv);
+        if (aRv.Failed()) {
+          return;
+        }
+      }
+      if (guard.Mutated(1) && !ValidateCurrentNode(this, iter)) {
+        aRv.Throw(NS_ERROR_UNEXPECTED);
+        return;
+      }
+    }
+
+    if (!iter.IsDone() && retval) {
+      // Find the equivalent of commonAncestor in the cloned tree.
+      nsCOMPtr<nsINode> newCloneAncestor = nodeToResult;
+      for (uint32_t i = parentCount; i; --i) {
+        newCloneAncestor = newCloneAncestor->GetParentNode();
+        if (!newCloneAncestor) {
+          aRv.Throw(NS_ERROR_UNEXPECTED);
+          return;
+        }
+      }
+      commonCloneAncestor = newCloneAncestor;
+    }
+  }
+
+  aRv = CollapseRangeAfterDelete(this);
+  if (!aRv.Failed() && aFragment) {
+    retval.forget(aFragment);
+  }
+}
+
+void nsRange::DeleteContents(ErrorResult& aRv) { CutContents(nullptr, aRv); }
+
+already_AddRefed<DocumentFragment> nsRange::ExtractContents(ErrorResult& rv) {
+  RefPtr<DocumentFragment> fragment;
+  CutContents(getter_AddRefs(fragment), rv);
+  return fragment.forget();
+}
+
+int16_t nsRange::CompareBoundaryPoints(uint16_t aHow,
+                                       const nsRange& aOtherRange,
+                                       ErrorResult& aRv) {
+  if (!mIsPositioned || !aOtherRange.IsPositioned()) {
+    aRv.Throw(NS_ERROR_NOT_INITIALIZED);
+    return 0;
+  }
+
+  nsINode *ourNode, *otherNode;
+  uint32_t ourOffset, otherOffset;
+
+  switch (aHow) {
+    case Range_Binding::START_TO_START:
+      ourNode = mStart.Container();
+      ourOffset = *mStart.Offset(RangeBoundary::OffsetFilter::kValidOffsets);
+      otherNode = aOtherRange.GetStartContainer();
+      otherOffset = aOtherRange.StartOffset();
+      break;
+    case Range_Binding::START_TO_END:
+      ourNode = mEnd.Container();
+      ourOffset = *mEnd.Offset(RangeBoundary::OffsetFilter::kValidOffsets);
+      otherNode = aOtherRange.GetStartContainer();
+      otherOffset = aOtherRange.StartOffset();
+      break;
+    case Range_Binding::END_TO_START:
+      ourNode = mStart.Container();
+      ourOffset = *mStart.Offset(RangeBoundary::OffsetFilter::kValidOffsets);
+      otherNode = aOtherRange.GetEndContainer();
+      otherOffset = aOtherRange.EndOffset();
+      break;
+    case Range_Binding::END_TO_END:
+      ourNode = mEnd.Container();
+      ourOffset = *mEnd.Offset(RangeBoundary::OffsetFilter::kValidOffsets);
+      otherNode = aOtherRange.GetEndContainer();
+      otherOffset = aOtherRange.EndOffset();
+      break;
+    default:
+      // We were passed an illegal value
+      aRv.Throw(NS_ERROR_DOM_NOT_SUPPORTED_ERR);
+      return 0;
+  }
+
+  if (mRoot != aOtherRange.GetRoot()) {
+    aRv.Throw(NS_ERROR_DOM_WRONG_DOCUMENT_ERR);
+    return 0;
+  }
+
+  const Maybe<int32_t> order =
+      nsContentUtils::ComparePoints(ourNode, ourOffset, otherNode, otherOffset);
+
+  // `this` and `aOtherRange` share the same root and (ourNode, ourOffset),
+  // (otherNode, otherOffset) correspond to some of their boundaries. Hence,
+  // (ourNode, ourOffset) and (otherNode, otherOffset) have to be comparable.
+  return *order;
+}
+
+/* static */
+nsresult nsRange::CloneParentsBetween(nsINode* aAncestor, nsINode* aNode,
+                                      nsINode** aClosestAncestor,
+                                      nsINode** aFarthestAncestor) {
+  NS_ENSURE_ARG_POINTER(
+      (aAncestor && aNode && aClosestAncestor && aFarthestAncestor));
+
+  *aClosestAncestor = nullptr;
+  *aFarthestAncestor = nullptr;
+
+  if (aAncestor == aNode) return NS_OK;
+
+  AutoTArray<nsCOMPtr<nsINode>, 16> parentStack;
+
+  nsCOMPtr<nsINode> parent = aNode->GetParentNode();
+  while (parent && parent != aAncestor) {
+    parentStack.AppendElement(parent);
+    parent = parent->GetParentNode();
+  }
+
+  nsCOMPtr<nsINode> firstParent;
+  nsCOMPtr<nsINode> lastParent;
+  for (int32_t i = parentStack.Length() - 1; i >= 0; i--) {
+    ErrorResult rv;
+    nsCOMPtr<nsINode> clone = parentStack[i]->CloneNode(false, rv);
+
+    if (rv.Failed()) {
+      return rv.StealNSResult();
+    }
+    if (!clone) {
+      return NS_ERROR_FAILURE;
+    }
+
+    if (!lastParent) {
+      lastParent = clone;
+    } else {
+      firstParent->AppendChild(*clone, rv);
+      if (rv.Failed()) {
+        return rv.StealNSResult();
+      }
+    }
+
+    firstParent = clone;
+  }
+
+  firstParent.forget(aClosestAncestor);
+  lastParent.forget(aFarthestAncestor);
+
+  return NS_OK;
+}
+
+already_AddRefed<DocumentFragment> nsRange::CloneContents(ErrorResult& aRv) {
+  nsCOMPtr<nsINode> commonAncestor = GetCommonAncestorContainer(aRv);
+  MOZ_ASSERT(!aRv.Failed(), "GetCommonAncestorContainer() shouldn't fail!");
+
+  nsCOMPtr<Document> doc = mStart.Container()->OwnerDoc();
+  NS_ASSERTION(doc, "CloneContents needs a document to continue.");
+  if (!doc) {
+    aRv.Throw(NS_ERROR_FAILURE);
+    return nullptr;
+  }
+
+  // Create a new document fragment in the context of this document,
+  // which might be null
+
+  RefPtr<DocumentFragment> clonedFrag =
+      new (doc->NodeInfoManager()) DocumentFragment(doc->NodeInfoManager());
+
+  if (Collapsed()) {
+    return clonedFrag.forget();
+  }
+
+  nsCOMPtr<nsINode> commonCloneAncestor = clonedFrag.get();
+
+  // Create and initialize a subtree iterator that will give
+  // us all the subtrees within the range.
+
+  RangeSubtreeIterator iter;
+
+  aRv = iter.Init(this);
+  if (aRv.Failed()) {
+    return nullptr;
+  }
+
+  if (iter.IsDone()) {
+    // There's nothing to add to the doc frag, we must be done!
+    return clonedFrag.forget();
+  }
+
+  iter.First();
+
+  // With the exception of text nodes that contain one of the range
+  // end points and elements which don't have any content selected the subtree
+  // iterator should only give us back subtrees that are completely contained
+  // between the range's end points.
+  //
+  // Unfortunately these subtrees don't contain the parent hierarchy/context
+  // that the Range spec requires us to return. This loop clones the
+  // parent hierarchy, adds a cloned version of the subtree, to it, then
+  // correctly places this new subtree into the doc fragment.
+
+  while (!iter.IsDone()) {
+    nsCOMPtr<nsINode> node = iter.GetCurrentNode();
+    bool deepClone =
+        !node->IsElement() ||
+        (!(node == mEnd.Container() &&
+           *mEnd.Offset(RangeBoundary::OffsetFilter::kValidOffsets) == 0) &&
+         !(node == mStart.Container() &&
+           *mStart.Offset(RangeBoundary::OffsetFilter::kValidOffsets) ==
+               node->AsElement()->GetChildCount()));
+
+    // Clone the current subtree!
+
+    nsCOMPtr<nsINode> clone = node->CloneNode(deepClone, aRv);
+    if (aRv.Failed()) {
+      return nullptr;
+    }
+
+    // If it's CharacterData, make sure we only clone what
+    // is in the range.
+    //
+    // XXX_kin: We need to also handle ProcessingInstruction
+    // XXX_kin: according to the spec.
+
+    if (auto charData = CharacterData::FromNode(clone)) {
+      if (node == mEnd.Container()) {
+        // We only need the data before mEndOffset, so get rid of any
+        // data after it.
+
+        uint32_t dataLength = charData->Length();
+        if (dataLength >
+            *mEnd.Offset(RangeBoundary::OffsetFilter::kValidOffsets)) {
+          charData->DeleteData(
+              *mEnd.Offset(RangeBoundary::OffsetFilter::kValidOffsets),
+              dataLength -
+                  *mEnd.Offset(RangeBoundary::OffsetFilter::kValidOffsets),
+              aRv);
+          if (aRv.Failed()) {
+            return nullptr;
+          }
+        }
+      }
+
+      if (node == mStart.Container()) {
+        // We don't need any data before mStartOffset, so just
+        // delete it!
+
+        if (*mStart.Offset(RangeBoundary::OffsetFilter::kValidOffsets) > 0) {
+          charData->DeleteData(
+              0, *mStart.Offset(RangeBoundary::OffsetFilter::kValidOffsets),
+              aRv);
+          if (aRv.Failed()) {
+            return nullptr;
+          }
+        }
+      }
+    }
+
+    // Clone the parent hierarchy between commonAncestor and node.
+
+    nsCOMPtr<nsINode> closestAncestor, farthestAncestor;
+
+    aRv = CloneParentsBetween(commonAncestor, node,
+                              getter_AddRefs(closestAncestor),
+                              getter_AddRefs(farthestAncestor));
+
+    if (aRv.Failed()) {
+      return nullptr;
+    }
+
+    // Hook the parent hierarchy/context of the subtree into the clone tree.
+
+    if (farthestAncestor) {
+      commonCloneAncestor->AppendChild(*farthestAncestor, aRv);
+
+      if (aRv.Failed()) {
+        return nullptr;
+      }
+    }
+
+    // Place the cloned subtree into the cloned doc frag tree!
+
+    nsCOMPtr<nsINode> cloneNode = clone;
+    if (closestAncestor) {
+      // Append the subtree under closestAncestor since it is the
+      // immediate parent of the subtree.
+
+      closestAncestor->AppendChild(*cloneNode, aRv);
+    } else {
+      // If we get here, there is no missing parent hierarchy between
+      // commonAncestor and node, so just append clone to commonCloneAncestor.
+
+      commonCloneAncestor->AppendChild(*cloneNode, aRv);
+    }
+    if (aRv.Failed()) {
+      return nullptr;
+    }
+
+    // Get the next subtree to be processed. The idea here is to setup
+    // the parameters for the next iteration of the loop.
+
+    iter.Next();
+
+    if (iter.IsDone()) break;  // We must be done!
+
+    nsCOMPtr<nsINode> nextNode = iter.GetCurrentNode();
+    if (!nextNode) {
+      aRv.Throw(NS_ERROR_FAILURE);
+      return nullptr;
+    }
+
+    // Get node and nextNode's common parent.
+    commonAncestor =
+        nsContentUtils::GetClosestCommonInclusiveAncestor(node, nextNode);
+
+    if (!commonAncestor) {
+      aRv.Throw(NS_ERROR_FAILURE);
+      return nullptr;
+    }
+
+    // Find the equivalent of commonAncestor in the cloned tree!
+
+    while (node && node != commonAncestor) {
+      node = node->GetParentNode();
+      if (aRv.Failed()) {
+        return nullptr;
+      }
+
+      if (!node) {
+        aRv.Throw(NS_ERROR_FAILURE);
+        return nullptr;
+      }
+
+      cloneNode = cloneNode->GetParentNode();
+      if (!cloneNode) {
+        aRv.Throw(NS_ERROR_FAILURE);
+        return nullptr;
+      }
+    }
+
+    commonCloneAncestor = cloneNode;
+  }
+
+  return clonedFrag.forget();
+}
+
+already_AddRefed<nsRange> nsRange::CloneRange() const {
+  RefPtr<nsRange> range = nsRange::Create(mOwner);
+  range->DoSetRange(mStart, mEnd, mRoot);
+  return range.forget();
+}
+
+void nsRange::InsertNode(nsINode& aNode, ErrorResult& aRv) {
+  if (!CanAccess(aNode)) {
+    aRv.Throw(NS_ERROR_DOM_SECURITY_ERR);
+    return;
+  }
+
+  if (!IsPositioned()) {
+    aRv.Throw(NS_ERROR_NOT_INITIALIZED);
+    return;
+  }
+
+  uint32_t tStartOffset = StartOffset();
+
+  nsCOMPtr<nsINode> tStartContainer = GetStartContainer();
+
+  if (!CanAccess(*tStartContainer)) {
+    aRv.Throw(NS_ERROR_DOM_SECURITY_ERR);
+    return;
+  }
+
+  if (&aNode == tStartContainer) {
+    aRv.ThrowHierarchyRequestError(
+        "The inserted node can not be range's start node.");
+    return;
+  }
+
+  // This is the node we'll be inserting before, and its parent
+  nsCOMPtr<nsINode> referenceNode;
+  nsCOMPtr<nsINode> referenceParentNode = tStartContainer;
+
+  RefPtr<Text> startTextNode = tStartContainer->GetAsText();
+  nsCOMPtr<nsINodeList> tChildList;
+  if (startTextNode) {
+    referenceParentNode = tStartContainer->GetParentNode();
+    if (!referenceParentNode) {
+      aRv.ThrowHierarchyRequestError(
+          "Can not get range's start node's parent.");
+      return;
+    }
+
+    referenceParentNode->EnsurePreInsertionValidity(aNode, tStartContainer,
+                                                    aRv);
+    if (aRv.Failed()) {
+      return;
+    }
+
+    RefPtr<Text> secondPart = startTextNode->SplitText(tStartOffset, aRv);
+    if (aRv.Failed()) {
+      return;
+    }
+
+    referenceNode = secondPart;
+  } else {
+    tChildList = tStartContainer->ChildNodes();
+
+    // find the insertion point in the DOM and insert the Node
+    referenceNode = tChildList->Item(tStartOffset);
+
+    tStartContainer->EnsurePreInsertionValidity(aNode, referenceNode, aRv);
+    if (aRv.Failed()) {
+      return;
+    }
+  }
+
+  // We might need to update the end to include the new node (bug 433662).
+  // Ideally we'd only do this if needed, but it's tricky to know when it's
+  // needed in advance (bug 765799).
+  uint32_t newOffset;
+
+  if (referenceNode) {
+    Maybe<uint32_t> indexInParent = referenceNode->ComputeIndexInParentNode();
+    if (MOZ_UNLIKELY(NS_WARN_IF(indexInParent.isNothing()))) {
+      aRv.Throw(NS_ERROR_FAILURE);
+      return;
+    }
+    newOffset = *indexInParent;
+  } else {
+    newOffset = tChildList->Length();
+  }
+
+  if (aNode.NodeType() == nsINode::DOCUMENT_FRAGMENT_NODE) {
+    newOffset += aNode.GetChildCount();
+  } else {
+    newOffset++;
+  }
+
+  // Now actually insert the node
+  nsCOMPtr<nsINode> tResultNode;
+  tResultNode = referenceParentNode->InsertBefore(aNode, referenceNode, aRv);
+  if (aRv.Failed()) {
+    return;
+  }
+
+  if (Collapsed()) {
+    aRv = SetEnd(referenceParentNode, newOffset);
+  }
+}
+
+void nsRange::SurroundContents(nsINode& aNewParent, ErrorResult& aRv) {
+  if (!CanAccess(aNewParent)) {
+    aRv.Throw(NS_ERROR_DOM_SECURITY_ERR);
+    return;
+  }
+
+  if (!mRoot) {
+    aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
+    return;
+  }
+  // INVALID_STATE_ERROR: Raised if the Range partially selects a non-text
+  // node.
+  if (mStart.Container() != mEnd.Container()) {
+    bool startIsText = mStart.Container()->IsText();
+    bool endIsText = mEnd.Container()->IsText();
+    nsINode* startGrandParent = mStart.Container()->GetParentNode();
+    nsINode* endGrandParent = mEnd.Container()->GetParentNode();
+    if (!((startIsText && endIsText && startGrandParent &&
+           startGrandParent == endGrandParent) ||
+          (startIsText && startGrandParent &&
+           startGrandParent == mEnd.Container()) ||
+          (endIsText && endGrandParent &&
+           endGrandParent == mStart.Container()))) {
+      aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
+      return;
+    }
+  }
+
+  // INVALID_NODE_TYPE_ERROR if aNewParent is something that can't be inserted
+  // (Document, DocumentType, DocumentFragment)
+  uint16_t nodeType = aNewParent.NodeType();
+  if (nodeType == nsINode::DOCUMENT_NODE ||
+      nodeType == nsINode::DOCUMENT_TYPE_NODE ||
+      nodeType == nsINode::DOCUMENT_FRAGMENT_NODE) {
+    aRv.Throw(NS_ERROR_DOM_INVALID_NODE_TYPE_ERR);
+    return;
+  }
+
+  // Extract the contents within the range.
+
+  RefPtr<DocumentFragment> docFrag = ExtractContents(aRv);
+
+  if (aRv.Failed()) {
+    return;
+  }
+
+  if (!docFrag) {
+    aRv.Throw(NS_ERROR_FAILURE);
+    return;
+  }
+
+  // Spec says we need to remove all of aNewParent's
+  // children prior to insertion.
+
+  nsCOMPtr<nsINodeList> children = aNewParent.ChildNodes();
+  if (!children) {
+    aRv.Throw(NS_ERROR_FAILURE);
+    return;
+  }
+
+  uint32_t numChildren = children->Length();
+
+  while (numChildren) {
+    nsCOMPtr<nsINode> child = children->Item(--numChildren);
+    if (!child) {
+      aRv.Throw(NS_ERROR_FAILURE);
+      return;
+    }
+
+    aNewParent.RemoveChild(*child, aRv);
+    if (aRv.Failed()) {
+      return;
+    }
+  }
+
+  // Insert aNewParent at the range's start point.
+
+  InsertNode(aNewParent, aRv);
+  if (aRv.Failed()) {
+    return;
+  }
+
+  // Append the content we extracted under aNewParent.
+  aNewParent.AppendChild(*docFrag, aRv);
+  if (aRv.Failed()) {
+    return;
+  }
+
+  // Select aNewParent, and its contents.
+
+  SelectNode(aNewParent, aRv);
+}
+
+void nsRange::ToString(nsAString& aReturn, ErrorResult& aErr) {
+  // clear the string
+  aReturn.Truncate();
+
+  // If we're unpositioned, return the empty string
+  if (!mIsPositioned) {
+    return;
+  }
+
+#ifdef DEBUG_range
+  printf("Range dump: -----------------------\n");
+#endif /* DEBUG */
+
+  // effeciency hack for simple case
+  if (mStart.Container() == mEnd.Container()) {
+    Text* textNode =
+        mStart.Container() ? mStart.Container()->GetAsText() : nullptr;
+
+    if (textNode) {
+#ifdef DEBUG_range
+      // If debug, dump it:
+      textNode->List(stdout);
+      printf("End Range dump: -----------------------\n");
+#endif /* DEBUG */
+
+      // grab the text
+      textNode->SubstringData(
+          *mStart.Offset(RangeBoundary::OffsetFilter::kValidOffsets),
+          *mEnd.Offset(RangeBoundary::OffsetFilter::kValidOffsets) -
+              *mStart.Offset(RangeBoundary::OffsetFilter::kValidOffsets),
+          aReturn, aErr);
+      return;
+    }
+  }
+
+  /* complex case: mStart.Container() != mEnd.Container(), or mStartParent not a
+     text node revisit - there are potential optimizations here and also
+     tradeoffs.
+  */
+
+  PostContentIterator postOrderIter;
+  nsresult rv = postOrderIter.Init(this);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    aErr.Throw(rv);
+    return;
+  }
+
+  nsString tempString;
+
+  // loop through the content iterator, which returns nodes in the range in
+  // close tag order, and grab the text from any text node
+  for (; !postOrderIter.IsDone(); postOrderIter.Next()) {
+    nsINode* n = postOrderIter.GetCurrentNode();
+
+#ifdef DEBUG_range
+    // If debug, dump it:
+    n->List(stdout);
+#endif /* DEBUG */
+    Text* textNode = n->GetAsText();
+    if (textNode)  // if it's a text node, get the text
+    {
+      if (n == mStart.Container()) {  // only include text past start offset
+        uint32_t strLength = textNode->Length();
+        textNode->SubstringData(
+            *mStart.Offset(RangeBoundary::OffsetFilter::kValidOffsets),
+            strLength -
+                *mStart.Offset(RangeBoundary::OffsetFilter::kValidOffsets),
+            tempString, IgnoreErrors());
+        aReturn += tempString;
+      } else if (n ==
+                 mEnd.Container()) {  // only include text before end offset
+        textNode->SubstringData(
+            0, *mEnd.Offset(RangeBoundary::OffsetFilter::kValidOffsets),
+            tempString, IgnoreErrors());
+        aReturn += tempString;
+      } else {  // grab the whole kit-n-kaboodle
+        textNode->GetData(tempString);
+        aReturn += tempString;
+      }
+    }
+  }
+
+#ifdef DEBUG_range
+  printf("End Range dump: -----------------------\n");
+#endif /* DEBUG */
+}
+
+void nsRange::Detach() {}
+
+already_AddRefed<DocumentFragment> nsRange::CreateContextualFragment(
+    const nsAString& aFragment, ErrorResult& aRv) const {
+  if (!mIsPositioned) {
+    aRv.Throw(NS_ERROR_FAILURE);
+    return nullptr;
+  }
+
+  return nsContentUtils::CreateContextualFragment(mStart.Container(), aFragment,
+                                                  false, aRv);
+}
+
+static void ExtractRectFromOffset(nsIFrame* aFrame, const int32_t aOffset,
+                                  nsRect* aR, bool aFlushToOriginEdge,
+                                  bool aClampToEdge) {
+  MOZ_ASSERT(aFrame);
+  MOZ_ASSERT(aR);
+
+  nsPoint point;
+  aFrame->GetPointFromOffset(aOffset, &point);
+
+  // Determine if aFrame has a vertical writing mode, which will change our math
+  // on the output rect.
+  bool isVertical = aFrame->GetWritingMode().IsVertical();
+
+  if (!aClampToEdge && !aR->Contains(point)) {
+    // If point is outside aR, and we aren't clamping, output an empty rect
+    // with origin at the point.
+    if (isVertical) {
+      aR->SetHeight(0);
+      aR->y = point.y;
+    } else {
+      aR->SetWidth(0);
+      aR->x = point.x;
+    }
+    return;
+  }
+
+  if (aClampToEdge) {
+    point = aR->ClampPoint(point);
+  }
+
+  // point is within aR, and now we'll modify aR to output a rect that has point
+  // on one edge. But which edge?
+  if (aFlushToOriginEdge) {
+    // The output rect should be flush to the edge of aR that contains the
+    // origin.
+    if (isVertical) {
+      aR->SetHeight(point.y - aR->y);
+    } else {
+      aR->SetWidth(point.x - aR->x);
+    }
+  } else {
+    // The output rect should be flush to the edge of aR opposite the origin.
+    if (isVertical) {
+      aR->SetHeight(aR->YMost() - point.y);
+      aR->y = point.y;
+    } else {
+      aR->SetWidth(aR->XMost() - point.x);
+      aR->x = point.x;
+    }
+  }
+}
+
+static nsTextFrame* GetTextFrameForContent(nsIContent* aContent,
+                                           bool aFlushLayout) {
+  RefPtr<Document> doc = aContent->OwnerDoc();
+  PresShell* presShell = doc->GetPresShell();
+  if (!presShell) {
+    return nullptr;
+  }
+
+  // Try to un-suppress whitespace if needed, but only if we'll be able to flush
+  // to immediately see the results of the un-suppression. If we can't flush
+  // here, then calling EnsureFrameForTextNodeIsCreatedAfterFlush would be
+  // pointless anyway.
+  if (aFlushLayout) {
+    const bool frameWillBeUnsuppressed =
+        presShell->FrameConstructor()
+            ->EnsureFrameForTextNodeIsCreatedAfterFlush(
+                static_cast<CharacterData*>(aContent));
+    if (frameWillBeUnsuppressed) {
+      doc->FlushPendingNotifications(FlushType::Layout);
+    }
+  }
+
+  nsIFrame* frame = aContent->GetPrimaryFrame();
+  if (!frame || !frame->IsTextFrame()) {
+    return nullptr;
+  }
+  return static_cast<nsTextFrame*>(frame);
+}
+
+static nsresult GetPartialTextRect(RectCallback* aCallback,
+                                   Sequence<nsString>* aTextList,
+                                   nsIContent* aContent, int32_t aStartOffset,
+                                   int32_t aEndOffset, bool aClampToEdge,
+                                   bool aFlushLayout) {
+  nsTextFrame* textFrame = GetTextFrameForContent(aContent, aFlushLayout);
+  if (textFrame) {
+    nsIFrame* relativeTo =
+        nsLayoutUtils::GetContainingBlockForClientRect(textFrame);
+
+    for (nsTextFrame* f = textFrame->FindContinuationForOffset(aStartOffset); f;
+         f = static_cast<nsTextFrame*>(f->GetNextContinuation())) {
+      int32_t fstart = f->GetContentOffset(), fend = f->GetContentEnd();
+      if (fend <= aStartOffset) {
+        continue;
+      }
+      if (fstart >= aEndOffset) {
+        break;
+      }
+
+      // Calculate the text content offsets we'll need if text is requested.
+      int32_t textContentStart = fstart;
+      int32_t textContentEnd = fend;
+
+      // overlapping with the offset we want
+      f->EnsureTextRun(nsTextFrame::eInflated);
+      NS_ENSURE_TRUE(f->GetTextRun(nsTextFrame::eInflated),
+                     NS_ERROR_OUT_OF_MEMORY);
+      bool topLeftToBottomRight =
+          !f->GetTextRun(nsTextFrame::eInflated)->IsInlineReversed();
+      nsRect r = f->GetRectRelativeToSelf();
+      if (fstart < aStartOffset) {
+        // aStartOffset is within this frame
+        ExtractRectFromOffset(f, aStartOffset, &r, !topLeftToBottomRight,
+                              aClampToEdge);
+        textContentStart = aStartOffset;
+      }
+      if (fend > aEndOffset) {
+        // aEndOffset is in the middle of this frame
+        ExtractRectFromOffset(f, aEndOffset, &r, topLeftToBottomRight,
+                              aClampToEdge);
+        textContentEnd = aEndOffset;
+      }
+      r = nsLayoutUtils::TransformFrameRectToAncestor(f, r, relativeTo);
+      aCallback->AddRect(r);
+
+      // Finally capture the text, if requested.
+      if (aTextList) {
+        nsIFrame::RenderedText renderedText =
+            f->GetRenderedText(textContentStart, textContentEnd,
+                               nsIFrame::TextOffsetType::OffsetsInContentText,
+                               nsIFrame::TrailingWhitespace::DontTrim);
+
+        NS_ENSURE_TRUE(aTextList->AppendElement(renderedText.mString, fallible),
+                       NS_ERROR_OUT_OF_MEMORY);
+      }
+    }
+  }
+  return NS_OK;
+}
+
+static void CollectClientRectsForSubtree(
+    nsINode* aNode, RectCallback* aCollector, Sequence<nsString>* aTextList,
+    nsINode* aStartContainer, uint32_t aStartOffset, nsINode* aEndContainer,
+    uint32_t aEndOffset, bool aClampToEdge, bool aFlushLayout) {
+  auto* content = nsIContent::FromNode(aNode);
+  if (!content) {
+    return;
+  }
+
+  if (content->IsText()) {
+    if (aNode == aStartContainer) {
+      int32_t offset = aStartContainer == aEndContainer
+                           ? static_cast<int32_t>(aEndOffset)
+                           : content->AsText()->TextDataLength();
+      GetPartialTextRect(aCollector, aTextList, content,
+                         static_cast<int32_t>(aStartOffset), offset,
+                         aClampToEdge, aFlushLayout);
+      return;
+    }
+
+    if (aNode == aEndContainer) {
+      GetPartialTextRect(aCollector, aTextList, content, 0,
+                         static_cast<int32_t>(aEndOffset), aClampToEdge,
+                         aFlushLayout);
+      return;
+    }
+  }
+
+  if (aNode->IsElement() && aNode->AsElement()->IsDisplayContents()) {
+    FlattenedChildIterator childIter(content);
+
+    for (nsIContent* child = childIter.GetNextChild(); child;
+         child = childIter.GetNextChild()) {
+      CollectClientRectsForSubtree(child, aCollector, aTextList,
+                                   aStartContainer, aStartOffset, aEndContainer,
+                                   aEndOffset, aClampToEdge, aFlushLayout);
+    }
+  } else if (nsIFrame* frame = content->GetPrimaryFrame()) {
+    nsLayoutUtils::GetAllInFlowRectsAndTexts(
+        frame, nsLayoutUtils::GetContainingBlockForClientRect(frame),
+        aCollector, aTextList, nsLayoutUtils::RECTS_ACCOUNT_FOR_TRANSFORMS);
+  }
+}
+
+/* static */
+void nsRange::CollectClientRectsAndText(
+    RectCallback* aCollector, Sequence<nsString>* aTextList, nsRange* aRange,
+    nsINode* aStartContainer, uint32_t aStartOffset, nsINode* aEndContainer,
+    uint32_t aEndOffset, bool aClampToEdge, bool aFlushLayout) {
+  // Currently, this method is called with start of end offset of nsRange.
+  // So, they must be between 0 - INT32_MAX.
+  MOZ_ASSERT(RangeUtils::IsValidOffset(aStartOffset));
+  MOZ_ASSERT(RangeUtils::IsValidOffset(aEndOffset));
+
+  // Hold strong pointers across the flush
+  nsCOMPtr<nsINode> startContainer = aStartContainer;
+  nsCOMPtr<nsINode> endContainer = aEndContainer;
+
+  // Flush out layout so our frames are up to date.
+  if (!aStartContainer->IsInComposedDoc()) {
+    return;
+  }
+
+  if (aFlushLayout) {
+    aStartContainer->OwnerDoc()->FlushPendingNotifications(FlushType::Layout);
+    // Recheck whether we're still in the document
+    if (!aStartContainer->IsInComposedDoc()) {
+      return;
+    }
+  }
+
+  RangeSubtreeIterator iter;
+
+  nsresult rv = iter.Init(aRange);
+  if (NS_FAILED(rv)) return;
+
+  if (iter.IsDone()) {
+    // the range is collapsed, only continue if the cursor is in a text node
+    if (aStartContainer->IsText()) {
+      nsTextFrame* textFrame =
+          GetTextFrameForContent(aStartContainer->AsText(), aFlushLayout);
+      if (textFrame) {
+        int32_t outOffset;
+        nsIFrame* outFrame;
+        textFrame->GetChildFrameContainingOffset(
+            static_cast<int32_t>(aStartOffset), false, &outOffset, &outFrame);
+        if (outFrame) {
+          nsIFrame* relativeTo =
+              nsLayoutUtils::GetContainingBlockForClientRect(outFrame);
+          nsRect r = outFrame->GetRectRelativeToSelf();
+          ExtractRectFromOffset(outFrame, static_cast<int32_t>(aStartOffset),
+                                &r, false, aClampToEdge);
+          r.SetWidth(0);
+          r = nsLayoutUtils::TransformFrameRectToAncestor(outFrame, r,
+                                                          relativeTo);
+          aCollector->AddRect(r);
+        }
+      }
+    }
+    return;
+  }
+
+  do {
+    nsCOMPtr<nsINode> node = iter.GetCurrentNode();
+    iter.Next();
+
+    CollectClientRectsForSubtree(node, aCollector, aTextList, aStartContainer,
+                                 aStartOffset, aEndContainer, aEndOffset,
+                                 aClampToEdge, aFlushLayout);
+  } while (!iter.IsDone());
+}
+
+already_AddRefed<DOMRect> nsRange::GetBoundingClientRect(bool aClampToEdge,
+                                                         bool aFlushLayout) {
+  RefPtr<DOMRect> rect = new DOMRect(ToSupports(mOwner));
+  if (!mIsPositioned) {
+    return rect.forget();
+  }
+
+  nsLayoutUtils::RectAccumulator accumulator;
+  CollectClientRectsAndText(
+      &accumulator, nullptr, this, mStart.Container(),
+      *mStart.Offset(RangeBoundary::OffsetFilter::kValidOffsets),
+      mEnd.Container(),
+      *mEnd.Offset(RangeBoundary::OffsetFilter::kValidOffsets), aClampToEdge,
+      aFlushLayout);
+
+  nsRect r = accumulator.mResultRect.IsEmpty() ? accumulator.mFirstRect
+                                               : accumulator.mResultRect;
+  rect->SetLayoutRect(r);
+  return rect.forget();
+}
+
+already_AddRefed<DOMRectList> nsRange::GetClientRects(bool aClampToEdge,
+                                                      bool aFlushLayout) {
+  if (!mIsPositioned) {
+    return nullptr;
+  }
+
+  RefPtr<DOMRectList> rectList = new DOMRectList(ToSupports(mOwner));
+
+  nsLayoutUtils::RectListBuilder builder(rectList);
+
+  CollectClientRectsAndText(
+      &builder, nullptr, this, mStart.Container(),
+      *mStart.Offset(RangeBoundary::OffsetFilter::kValidOffsets),
+      mEnd.Container(),
+      *mEnd.Offset(RangeBoundary::OffsetFilter::kValidOffsets), aClampToEdge,
+      aFlushLayout);
+  return rectList.forget();
+}
+
+void nsRange::GetClientRectsAndTexts(mozilla::dom::ClientRectsAndTexts& aResult,
+                                     ErrorResult& aErr) {
+  if (!mIsPositioned) {
+    return;
+  }
+
+  aResult.mRectList = new DOMRectList(ToSupports(mOwner));
+
+  nsLayoutUtils::RectListBuilder builder(aResult.mRectList);
+
+  CollectClientRectsAndText(
+      &builder, &aResult.mTextList, this, mStart.Container(),
+      *mStart.Offset(RangeBoundary::OffsetFilter::kValidOffsets),
+      mEnd.Container(),
+      *mEnd.Offset(RangeBoundary::OffsetFilter::kValidOffsets), true, true);
+}
+
+nsresult nsRange::GetUsedFontFaces(nsLayoutUtils::UsedFontFaceList& aResult,
+                                   uint32_t aMaxRanges,
+                                   bool aSkipCollapsedWhitespace) {
+  NS_ENSURE_TRUE(mIsPositioned, NS_ERROR_UNEXPECTED);
+
+  nsCOMPtr<nsINode> startContainer = mStart.Container();
+  nsCOMPtr<nsINode> endContainer = mEnd.Container();
+
+  // Flush out layout so our frames are up to date.
+  Document* doc = mStart.Container()->OwnerDoc();
+  NS_ENSURE_TRUE(doc, NS_ERROR_UNEXPECTED);
+  doc->FlushPendingNotifications(FlushType::Frames);
+
+  // Recheck whether we're still in the document
+  NS_ENSURE_TRUE(mStart.Container()->IsInComposedDoc(), NS_ERROR_UNEXPECTED);
+
+  // A table to map gfxFontEntry objects to InspectorFontFace objects.
+  // This table does NOT own the InspectorFontFace objects, it only holds
+  // raw pointers to them. They are owned by the aResult array.
+  nsLayoutUtils::UsedFontFaceTable fontFaces;
+
+  RangeSubtreeIterator iter;
+  nsresult rv = iter.Init(this);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  while (!iter.IsDone()) {
+    // only collect anything if the range is not collapsed
+    nsCOMPtr<nsINode> node = iter.GetCurrentNode();
+    iter.Next();
+
+    nsCOMPtr<nsIContent> content = do_QueryInterface(node);
+    if (!content) {
+      continue;
+    }
+    nsIFrame* frame = content->GetPrimaryFrame();
+    if (!frame) {
+      continue;
+    }
+
+    if (content->IsText()) {
+      if (node == startContainer) {
+        int32_t offset =
+            startContainer == endContainer
+                ? *mEnd.Offset(RangeBoundary::OffsetFilter::kValidOffsets)
+                : content->AsText()->TextDataLength();
+        nsLayoutUtils::GetFontFacesForText(
+            frame, *mStart.Offset(RangeBoundary::OffsetFilter::kValidOffsets),
+            offset, true, aResult, fontFaces, aMaxRanges,
+            aSkipCollapsedWhitespace);
+        continue;
+      }
+      if (node == endContainer) {
+        nsLayoutUtils::GetFontFacesForText(
+            frame, 0, *mEnd.Offset(RangeBoundary::OffsetFilter::kValidOffsets),
+            true, aResult, fontFaces, aMaxRanges, aSkipCollapsedWhitespace);
+        continue;
+      }
+    }
+
+    nsLayoutUtils::GetFontFacesForFrames(frame, aResult, fontFaces, aMaxRanges,
+                                         aSkipCollapsedWhitespace);
+  }
+
+  return NS_OK;
+}
+
+nsINode* nsRange::GetRegisteredClosestCommonInclusiveAncestor() {
+  MOZ_ASSERT(IsInAnySelection(),
+             "GetRegisteredClosestCommonInclusiveAncestor only valid for range "
+             "in selection");
+  MOZ_ASSERT(mRegisteredClosestCommonInclusiveAncestor);
+  return mRegisteredClosestCommonInclusiveAncestor;
+}
+
+/* static */
+bool nsRange::AutoInvalidateSelection::sIsNested;
+
+nsRange::AutoInvalidateSelection::~AutoInvalidateSelection() {
+  if (!mCommonAncestor) {
+    return;
+  }
+  sIsNested = false;
+  ::InvalidateAllFrames(mCommonAncestor);
+
+  // Our range might not be in a selection anymore, because one of our selection
+  // listeners might have gone ahead and run script of various sorts that messed
+  // with selections, ranges, etc.  But if it still is, we should check whether
+  // we have a different common ancestor now, and if so invalidate its subtree
+  // so it paints the selection it's in now.
+  if (mRange->IsInAnySelection()) {
+    nsINode* commonAncestor =
+        mRange->GetRegisteredClosestCommonInclusiveAncestor();
+    // XXXbz can commonAncestor really be null here?  I wouldn't think so!  If
+    // it _were_, then in a debug build
+    // GetRegisteredClosestCommonInclusiveAncestor() would have fatally
+    // asserted.
+    if (commonAncestor && commonAncestor != mCommonAncestor) {
+      ::InvalidateAllFrames(commonAncestor);
+    }
+  }
+}
+
+/* static */
+already_AddRefed<nsRange> nsRange::Constructor(const GlobalObject& aGlobal,
+                                               ErrorResult& aRv) {
+  nsCOMPtr<nsPIDOMWindowInner> window =
+      do_QueryInterface(aGlobal.GetAsSupports());
+  if (!window || !window->GetDoc()) {
+    aRv.Throw(NS_ERROR_FAILURE);
+    return nullptr;
+  }
+
+  return window->GetDoc()->CreateRange(aRv);
+}
+
+static bool ExcludeIfNextToNonSelectable(nsIContent* aContent) {
+  return aContent->IsText() &&
+         aContent->HasFlag(NS_CREATE_FRAME_IF_NON_WHITESPACE);
+}
+
+void nsRange::ExcludeNonSelectableNodes(nsTArray<RefPtr<nsRange>>* aOutRanges) {
+  if (!mIsPositioned) {
+    MOZ_ASSERT(false);
+    return;
+  }
+  MOZ_ASSERT(mEnd.Container());
+  MOZ_ASSERT(mStart.Container());
+
+  nsRange* range = this;
+  RefPtr<nsRange> newRange;
+  while (range) {
+    PreContentIterator preOrderIter;
+    nsresult rv = preOrderIter.Init(range);
+    if (NS_FAILED(rv)) {
+      return;
+    }
+
+    bool added = false;
+    bool seenSelectable = false;
+    // |firstNonSelectableContent| is the first node in a consecutive sequence
+    // of non-IsSelectable nodes.  When we find a selectable node after such
+    // a sequence we'll end the last nsRange, create a new one and restart
+    // the outer loop.
+    nsIContent* firstNonSelectableContent = nullptr;
+    while (true) {
+      nsINode* node = preOrderIter.GetCurrentNode();
+      preOrderIter.Next();
+      bool selectable = true;
+      nsIContent* content =
+          node && node->IsContent() ? node->AsContent() : nullptr;
+      if (content) {
+        if (firstNonSelectableContent &&
+            ExcludeIfNextToNonSelectable(content)) {
+          // Ignorable whitespace next to a sequence of non-selectable nodes
+          // counts as non-selectable (bug 1216001).
+          selectable = false;
+        }
+        if (selectable) {
+          nsIFrame* frame = content->GetPrimaryFrame();
+          for (nsIContent* p = content; !frame && (p = p->GetParent());) {
+            frame = p->GetPrimaryFrame();
+          }
+          if (frame) {
+            selectable = frame->IsSelectable(nullptr);
+          }
+        }
+      }
+
+      if (!selectable) {
+        if (!firstNonSelectableContent) {
+          firstNonSelectableContent = content;
+        }
+        if (preOrderIter.IsDone()) {
+          if (seenSelectable) {
+            // The tail end of the initial range is non-selectable - truncate
+            // the current range before the first non-selectable node.
+            range->SetEndBefore(*firstNonSelectableContent, IgnoreErrors());
+          }
+          return;
+        }
+        continue;
+      }
+
+      if (firstNonSelectableContent) {
+        if (range == this && !seenSelectable) {
+          // This is the initial range and all its nodes until now are
+          // non-selectable so just trim them from the start.
+          IgnoredErrorResult err;
+          range->SetStartBefore(*node, err);
+          if (err.Failed()) {
+            return;
+          }
+          break;  // restart the same range with a new iterator
+        }
+
+        // Save the end point before truncating the range.
+        nsINode* endContainer = range->mEnd.Container();
+        const uint32_t endOffset =
+            *range->mEnd.Offset(RangeBoundary::OffsetFilter::kValidOffsets);
+
+        // Truncate the current range before the first non-selectable node.
+        IgnoredErrorResult err;
+        range->SetEndBefore(*firstNonSelectableContent, err);
+
+        // Store it in the result (strong ref) - do this before creating
+        // a new range in |newRange| below so we don't drop the last ref
+        // to the range created in the previous iteration.
+        if (!added && !err.Failed()) {
+          aOutRanges->AppendElement(range);
+        }
+
+        // Create a new range for the remainder.
+        nsINode* startContainer = node;
+        Maybe<uint32_t> startOffset = Some(0);
+        // Don't start *inside* a node with independent selection though
+        // (e.g. <input>).
+        if (content && content->HasIndependentSelection()) {
+          nsINode* parent = startContainer->GetParent();
+          if (parent) {
+            startOffset = parent->ComputeIndexOf(startContainer);
+            startContainer = parent;
+          }
+        }
+        newRange =
+            nsRange::Create(startContainer, startOffset.valueOr(UINT32_MAX),
+                            endContainer, endOffset, IgnoreErrors());
+        if (!newRange || newRange->Collapsed()) {
+          newRange = nullptr;
+        }
+        range = newRange;
+        break;  // create a new iterator for the new range, if any
+      }
+
+      seenSelectable = true;
+      if (!added) {
+        added = true;
+        aOutRanges->AppendElement(range);
+      }
+      if (preOrderIter.IsDone()) {
+        return;
+      }
+    }
+  }
+}
+
+struct InnerTextAccumulator {
+  explicit InnerTextAccumulator(mozilla::dom::DOMString& aValue)
+      : mString(aValue.AsAString()), mRequiredLineBreakCount(0) {}
+  void FlushLineBreaks() {
+    while (mRequiredLineBreakCount > 0) {
+      // Required line breaks at the start of the text are suppressed.
+      if (!mString.IsEmpty()) {
+        mString.Append('\n');
+      }
+      --mRequiredLineBreakCount;
+    }
+  }
+  void Append(char aCh) { Append(nsAutoString(aCh)); }
+  void Append(const nsAString& aString) {
+    if (aString.IsEmpty()) {
+      return;
+    }
+    FlushLineBreaks();
+    mString.Append(aString);
+  }
+  void AddRequiredLineBreakCount(int8_t aCount) {
+    mRequiredLineBreakCount = std::max(mRequiredLineBreakCount, aCount);
+  }
+
+  nsAString& mString;
+  int8_t mRequiredLineBreakCount;
+};
+
+static bool IsVisibleAndNotInReplacedElement(nsIFrame* aFrame) {
+  if (!aFrame || !aFrame->StyleVisibility()->IsVisible() ||
+      aFrame->HasAnyStateBits(NS_FRAME_IS_NONDISPLAY)) {
+    return false;
+  }
+  if (aFrame->HidesContent()) {
+    return false;
+  }
+  for (nsIFrame* f = aFrame->GetParent(); f; f = f->GetParent()) {
+    if (f->HidesContent()) {
+      return false;
+    }
+    if (f->IsReplaced() &&
+        !f->GetContent()->IsAnyOfHTMLElements(nsGkAtoms::button,
+                                              nsGkAtoms::select) &&
+        !f->GetContent()->IsSVGElement()) {
+      return false;
+    }
+  }
+  return true;
+}
+
+static void AppendTransformedText(InnerTextAccumulator& aResult,
+                                  nsIContent* aContainer) {
+  auto textNode = static_cast<CharacterData*>(aContainer);
+
+  nsIFrame* frame = textNode->GetPrimaryFrame();
+  if (!IsVisibleAndNotInReplacedElement(frame)) {
+    return;
+  }
+
+  nsIFrame::RenderedText text =
+      frame->GetRenderedText(0, aContainer->GetChildCount());
+  aResult.Append(text.mString);
+}
+
+/**
+ * States for tree traversal. AT_NODE means that we are about to enter
+ * the current DOM node. AFTER_NODE means that we have just finished traversing
+ * the children of the current DOM node and are about to apply any
+ * "after processing the node's children" steps before we finish visiting
+ * the node.
+ */
+enum TreeTraversalState { AT_NODE, AFTER_NODE };
+
+static int8_t GetRequiredInnerTextLineBreakCount(nsIFrame* aFrame) {
+  if (aFrame->GetContent()->IsHTMLElement(nsGkAtoms::p)) {
+    return 2;
+  }
+  const nsStyleDisplay* styleDisplay = aFrame->StyleDisplay();
+  if (styleDisplay->IsBlockOutside(aFrame) ||
+      styleDisplay->mDisplay == StyleDisplay::TableCaption) {
+    return 1;
+  }
+  return 0;
+}
+
+static bool IsLastCellOfRow(nsIFrame* aFrame) {
+  LayoutFrameType type = aFrame->Type();
+  if (type != LayoutFrameType::TableCell) {
+    return true;
+  }
+  for (nsIFrame* c = aFrame; c; c = c->GetNextContinuation()) {
+    if (c->GetNextSibling()) {
+      return false;
+    }
+  }
+  return true;
+}
+
+static bool IsLastRowOfRowGroup(nsIFrame* aFrame) {
+  if (!aFrame->IsTableRowFrame()) {
+    return true;
+  }
+  for (nsIFrame* c = aFrame; c; c = c->GetNextContinuation()) {
+    if (c->GetNextSibling()) {
+      return false;
+    }
+  }
+  return true;
+}
+
+static bool IsLastNonemptyRowGroupOfTable(nsIFrame* aFrame) {
+  if (!aFrame->IsTableRowGroupFrame()) {
+    return true;
+  }
+  for (nsIFrame* c = aFrame; c; c = c->GetNextContinuation()) {
+    for (nsIFrame* next = c->GetNextSibling(); next;
+         next = next->GetNextSibling()) {
+      if (next->PrincipalChildList().FirstChild()) {
+        return false;
+      }
+    }
+  }
+  return true;
+}
+
+void nsRange::GetInnerTextNoFlush(DOMString& aValue, ErrorResult& aError,
+                                  nsIContent* aContainer) {
+  InnerTextAccumulator result(aValue);
+
+  if (aContainer->IsText()) {
+    AppendTransformedText(result, aContainer);
+    return;
+  }
+
+  nsIContent* currentNode = aContainer;
+  TreeTraversalState currentState = AFTER_NODE;
+
+  nsIContent* endNode = aContainer;
+  TreeTraversalState endState = AFTER_NODE;
+
+  nsIContent* firstChild = aContainer->GetFirstChild();
+  if (firstChild) {
+    currentNode = firstChild;
+    currentState = AT_NODE;
+  }
+
+  while (currentNode != endNode || currentState != endState) {
+    nsIFrame* f = currentNode->GetPrimaryFrame();
+    bool isVisibleAndNotReplaced = IsVisibleAndNotInReplacedElement(f);
+    if (currentState == AT_NODE) {
+      bool isText = currentNode->IsText();
+      if (isVisibleAndNotReplaced) {
+        result.AddRequiredLineBreakCount(GetRequiredInnerTextLineBreakCount(f));
+        if (isText) {
+          nsIFrame::RenderedText text = f->GetRenderedText();
+          result.Append(text.mString);
+        }
+      }
+      nsIContent* child = currentNode->GetFirstChild();
+      if (child) {
+        currentNode = child;
+        continue;
+      }
+      currentState = AFTER_NODE;
+    }
+    if (currentNode == endNode && currentState == endState) {
+      break;
+    }
+    if (isVisibleAndNotReplaced) {
+      if (currentNode->IsHTMLElement(nsGkAtoms::br)) {
+        result.Append('\n');
+      }
+      switch (f->StyleDisplay()->DisplayInside()) {
+        case StyleDisplayInside::TableCell:
+          if (!IsLastCellOfRow(f)) {
+            result.Append('\t');
+          }
+          break;
+        case StyleDisplayInside::TableRow:
+          if (!IsLastRowOfRowGroup(f) ||
+              !IsLastNonemptyRowGroupOfTable(f->GetParent())) {
+            result.Append('\n');
+          }
+          break;
+        default:
+          break;  // Do nothing
+      }
+      result.AddRequiredLineBreakCount(GetRequiredInnerTextLineBreakCount(f));
+    }
+    nsIContent* next = currentNode->GetNextSibling();
+    if (next) {
+      currentNode = next;
+      currentState = AT_NODE;
+    } else {
+      currentNode = currentNode->GetParent();
+    }
+  }
+
+  // Do not flush trailing line breaks! Required breaks at the end of the text
+  // are suppressed.
+}