CONTINUED Make FrameSelection to hold non-canonicalized positions

third_party/WebKit/Source/core/editing/SelectionEditor.cpp

Index: third_party/WebKit/Source/core/editing/SelectionEditor.cpp
diff --git a/third_party/WebKit/Source/core/editing/SelectionEditor.cpp b/third_party/WebKit/Source/core/editing/SelectionEditor.cpp
index 8206ecf15d3debae364272601af153a1bff8911d..42d97add4e8eeae89b1c5123b1f75228b9663e69 100644
--- a/third_party/WebKit/Source/core/editing/SelectionEditor.cpp
+++ b/third_party/WebKit/Source/core/editing/SelectionEditor.cpp
@@ -25,27 +25,56 @@
 
 #include "core/editing/SelectionEditor.h"
 
+#include "core/dom/NodeWithIndex.h"
+#include "core/dom/Text.h"
 #include "core/editing/EditingUtilities.h"
 #include "core/editing/Editor.h"
 #include "core/editing/SelectionAdjuster.h"
 #include "core/frame/LocalFrame.h"
+#include <iterator>
+#include <ostream>  // NOLINT
 
 namespace blink {
 
+#define FOR_EACH_STATE(V)       \
+  V(VisibleSelectionMayBeValid) \
+  V(DOMTreeIsChanged)           \
+  V(DOMTreeIsChanging)          \
+  V(SelectionInDOMTreeIsSource)
+
+enum class SelectionEditor::CacheState {
+#define V(name) name,
+  FOR_EACH_STATE(V)
+#undef V
+};
+
+std::ostream& operator<<(std::ostream& ostream,
+                         SelectionEditor::CacheState state) {
+  static const char* names[] = {
+#define V(name) #name,
+      FOR_EACH_STATE(V)
+#undef V
+  };
+  const auto& it = std::begin(names) + static_cast<size_t>(state);
+  if (it < std::begin(names) || it >= std::end(names))
+    return ostream << "CacheState::Bad(" << static_cast<int>(state) << ')';
+  return ostream << *it;
+}
+
 SelectionEditor::SelectionEditor(LocalFrame& frame)
-    : m_frame(frame), m_observingVisibleSelection(false) {
+    : m_frame(frame), m_cacheState(CacheState::VisibleSelectionMayBeValid) {
   clearVisibleSelection();
 }
 
 SelectionEditor::~SelectionEditor() {}
 
 void SelectionEditor::clearVisibleSelection() {
-  m_selection = VisibleSelection();
-  m_selectionInFlatTree = VisibleSelectionInFlatTree();
+  m_selection = SelectionInDOMTree();
+  m_cachedVisibleSelectionInDOMTree = VisibleSelection();
+  m_cachedVisibleSelectionInFlatTree = VisibleSelectionInFlatTree();
   if (!shouldAlwaysUseDirectionalSelection())
     return;
-  m_selection.setIsDirectional(true);
-  m_selectionInFlatTree.setIsDirectional(true);
+  m_selection.m_isDirectional = true;
 }
 
 void SelectionEditor::dispose() {
@@ -53,83 +82,356 @@ void SelectionEditor::dispose() {
   clearVisibleSelection();
 }
 
-const Document& SelectionEditor::document() const {
-  DCHECK(m_document);
-  return *m_document;
+Document& SelectionEditor::document() const {
+  DCHECK(lifecycleContext());
+  return *lifecycleContext();
+}
+
+const SelectionInDOMTree& SelectionEditor::selectionInDOMTree() const {
+  m_selection.assertValidFor(document());
+  return m_selection;
+}
+
+bool SelectionEditor::hasEditableStyle() const {
+  return computeVisibleSelectionInDOMTree().hasEditableStyle();
+}
+
+bool SelectionEditor::isContentEditable() const {
+  return computeVisibleSelectionInDOMTree().isContentEditable();
 }
 
-template <>
-const VisibleSelection& SelectionEditor::visibleSelection<EditingStrategy>()
+bool SelectionEditor::isContentRichlyEditable() const {
+  return computeVisibleSelectionInDOMTree().isContentRichlyEditable();
+}
+
+const VisibleSelection& SelectionEditor::computeVisibleSelectionInDOMTree()
     const {
   DCHECK_EQ(frame()->document(), document());
   DCHECK_EQ(frame(), document().frame());
-  if (m_selection.isNone())
-    return m_selection;
-  DCHECK_EQ(m_selection.base().document(), document());
-  return m_selection;
+  const_cast<SelectionEditor*>(this)->updateCachedVisibleSelectionIfNeeded();
+  if (m_cachedVisibleSelectionInDOMTree.isNone())
+    return m_cachedVisibleSelectionInDOMTree;
+  DCHECK_EQ(m_cachedVisibleSelectionInDOMTree.base().document(), document());
+  return m_cachedVisibleSelectionInDOMTree;
 }
 
-template <>
 const VisibleSelectionInFlatTree&
-SelectionEditor::visibleSelection<EditingInFlatTreeStrategy>() const {
+SelectionEditor::computeVisibleSelectionInFlatTree() const {
   DCHECK_EQ(frame()->document(), document());
   DCHECK_EQ(frame(), document().frame());
-  if (m_selectionInFlatTree.isNone())
-    return m_selectionInFlatTree;
-  DCHECK_EQ(m_selectionInFlatTree.base().document(), document());
-  return m_selectionInFlatTree;
+  const_cast<SelectionEditor*>(this)->updateCachedVisibleSelectionIfNeeded();
+  if (m_cachedVisibleSelectionInFlatTree.isNone())
+    return m_cachedVisibleSelectionInFlatTree;
+  DCHECK_EQ(m_cachedVisibleSelectionInFlatTree.base().document(), document());
+  return m_cachedVisibleSelectionInFlatTree;
 }
 
-void SelectionEditor::setVisibleSelection(
-    const VisibleSelection& newSelection,
-    FrameSelection::SetSelectionOptions options) {
-  DCHECK(newSelection.isValidFor(document())) << newSelection;
+void SelectionEditor::setSelection(const SelectionInDOMTree& newSelection) {
+  m_selection.assertValidFor(document());
+  newSelection.assertValidFor(document());
+  if (m_selection == newSelection)
+    return;
   resetLogicalRange();
+  m_cacheState = CacheState::SelectionInDOMTreeIsSource;
+  m_cachedVisibleSelectionInFlatTree = VisibleSelectionInFlatTree();
+  m_cachedVisibleSelectionInDOMTree = VisibleSelection();
+
   m_selection = newSelection;
-  if (options & FrameSelection::DoNotAdjustInFlatTree) {
-    m_selectionInFlatTree.setWithoutValidation(
-        toPositionInFlatTree(m_selection.base()),
-        toPositionInFlatTree(m_selection.extent()));
+
+  m_domTreeVersion = document().domTreeVersion();
+  m_styleVersion = document().styleVersion();
+}
+
+void SelectionEditor::didChangeAttribute(const Element&) {
+  didFinishDOMMutation();
+}
+
+void SelectionEditor::didChangeChildren(const ContainerNode&) {
+  didFinishDOMMutation();
+}
+
+void SelectionEditor::didMoveTreeToNewDocument() {
+  didFinishDOMMutation();
+}
+
+static Position computePositionForChildrenRemoval(const Position& position,
+                                                  ContainerNode& container) {
+  Node* node = position.computeContainerNode();
+  if (container.containsIncludingHostElements(*node))
+    return Position::firstPositionInNode(&container);
+  return position;
+}
+
+void SelectionEditor::nodeChildrenWillBeRemoved(ContainerNode& container) {
+  if (m_selection.isNone())
+    return;
+  const Position oldBase = m_selection.m_base;
+  const Position oldExtent = m_selection.m_extent;
+  const Position& newBase =
+      computePositionForChildrenRemoval(oldBase, container);
+  const Position& newExtent =
+      computePositionForChildrenRemoval(oldExtent, container);
+  if (newBase == oldBase && newExtent == oldExtent)
     return;
+  m_selection = SelectionInDOMTree::Builder()
+                    .setBaseAndExtent(newBase, newExtent)
+                    .build();
+  m_cachedVisibleSelectionInDOMTree = VisibleSelection();
+  m_cachedVisibleSelectionInFlatTree = VisibleSelectionInFlatTree();
+}
+
+static Position positionAfterPreviousSiblingOf(const Node& node) {
+  Node* const previousSibling = NodeTraversal::previousSibling(node);
+  if (!previousSibling) {
+    // Returns |BeforeChildren| of a parent of |node| since |node| is the
+    // first child.
+    return Position::firstPositionInNode(NodeTraversal::parent(node));
+  }
+#if 0
+  // When enable this code fragment,
+  // "editing/selection/mouse/drag-user-select-all-textarea.html" is failed.
+  //
+  // When disable this code fragment,
+  // "editing/selection/selection-after-text-normalize.html" is failed.
+  if (previousSibling->isCharacterDataNode()) {
+    return Position(previousSibling,
+                    toCharacterData(previousSibling)->length());
   }
+#endif
+  return Position::afterNode(previousSibling);
+}
 
-  SelectionAdjuster::adjustSelectionInFlatTree(&m_selectionInFlatTree,
-                                               m_selection);
+static Position computePositionForNodeRemoval(const Position& position,
+                                              Node& nodeToBeRemoved) {
+  Node* const anchorNode = position.anchorNode();
+  if (anchorNode == nodeToBeRemoved)
+    return positionAfterPreviousSiblingOf(nodeToBeRemoved);
+  if (position.isOffsetInAnchor() &&
+      anchorNode == nodeToBeRemoved.parentNode()) {
+    const int positionOffset = position.offsetInContainerNode();
+    if (positionOffset == 0)
+      return position;
+    // |nodeToBeRemoved| is sibling or itself of |position|.
+    int offset = 0;
+    for (Node& child :
+         NodeTraversal::childrenOf(*nodeToBeRemoved.parentNode())) {
+      if (nodeToBeRemoved == child) {
+        // |position| is after |nodeToBeRemoved|.
+        return Position(anchorNode, positionOffset - 1);
+      }
+      if (positionOffset == offset) {
+        // |position| is before |nodeToBeRemoved|.
+        return position;
+      }
+      ++offset;
+    }
+    NOTREACHED() << position << " should be handled.";
+  }
+  if (!nodeToBeRemoved.isContainerNode())
+    return position;
+  if (toContainerNode(nodeToBeRemoved)
+          .containsIncludingHostElements(*anchorNode))
+    return positionAfterPreviousSiblingOf(nodeToBeRemoved);
+  return position;
 }
 
-void SelectionEditor::setVisibleSelection(
-    const VisibleSelectionInFlatTree& newSelection,
-    FrameSelection::SetSelectionOptions options) {
-  DCHECK(newSelection.isValidFor(document())) << newSelection;
-  DCHECK(!(options & FrameSelection::DoNotAdjustInFlatTree));
-  resetLogicalRange();
-  m_selectionInFlatTree = newSelection;
-  SelectionAdjuster::adjustSelectionInDOMTree(&m_selection,
-                                              m_selectionInFlatTree);
+static Position updatePositionAfterAdoptingTextReplacement(
+    const Position& position,
+    CharacterData* node,
+    unsigned offset,
+    unsigned oldLength,
+    unsigned newLength) {
+  if (position.anchorNode() != node)
+    return position;
+
+  if (position.isBeforeAnchor()) {
+    return updatePositionAfterAdoptingTextReplacement(
+        Position(node, 0), node, offset, oldLength, newLength);
+  }
+  if (position.isAfterAnchor()) {
+    return updatePositionAfterAdoptingTextReplacement(
+        Position(node, oldLength), node, offset, oldLength, newLength);
+  }
+
+  // See:
+  // http://www.w3.org/TR/DOM-Level-2-Traversal-Range/ranges.html#Level-2-Range-Mutation
+  DCHECK_GE(position.offsetInContainerNode(), 0);
+  unsigned positionOffset =
+      static_cast<unsigned>(position.offsetInContainerNode());
+  // Replacing text can be viewed as a deletion followed by insertion.
+  if (positionOffset >= offset && positionOffset <= offset + oldLength)
+    positionOffset = offset;
+
+  // Adjust the offset if the position is after the end of the deleted contents
+  // (positionOffset > offset + oldLength) to avoid having a stale offset.
+  if (positionOffset > offset + oldLength)
+    positionOffset = positionOffset - oldLength + newLength;
+
+  // Due to case folding
+  // (http://unicode.org/Public/UCD/latest/ucd/CaseFolding.txt),
+  // LayoutText length may be different from Text length.  A correct
+  // implementation
+  // would translate the LayoutText offset to a Text offset; this is just a
+  // safety
+  // precaution to avoid offset values that run off the end of the Text.
+  if (positionOffset > node->length())
+    positionOffset = node->length();
+
+  return Position(node, positionOffset);
 }
 
-void SelectionEditor::setWithoutValidation(const Position& base,
-                                           const Position& extent) {
-  resetLogicalRange();
-  if (base.isNotNull())
-    DCHECK_EQ(base.document(), document());
-  if (extent.isNotNull())
-    DCHECK_EQ(extent.document(), document());
-  m_selection.setWithoutValidation(base, extent);
-  m_selectionInFlatTree.setWithoutValidation(toPositionInFlatTree(base),
-                                             toPositionInFlatTree(extent));
+void SelectionEditor::didUpdateCharacterData(CharacterData* node,
+                                             unsigned offset,
+                                             unsigned oldLength,
+                                             unsigned newLength) {
+  // The fragment check is a performance optimization. See
+  // http://trac.webkit.org/changeset/30062.
+  if (m_selection.isNone() || !node || !node->isConnected()) {
+    didFinishDOMMutation();
+    return;
+  }
+  const Position& newBase = updatePositionAfterAdoptingTextReplacement(
+      m_selection.m_base, node, offset, oldLength, newLength);
+  const Position& newExtent = updatePositionAfterAdoptingTextReplacement(
+      m_selection.m_extent, node, offset, oldLength, newLength);
+  didFinishTextChange(newBase, newExtent);
+}
+
+static Position updatePostionAfterAdoptingTextNodesMerged(
+    const Position& position,
+    const Text& mergedNode,
+    const NodeWithIndex& nodeToBeRemovedWithIndex,
+    unsigned oldLength) {
+  Node* const anchorNode = position.anchorNode();
+  const Node& nodeToBeRemoved = nodeToBeRemovedWithIndex.node();
+  switch (position.anchorType()) {
+    case PositionAnchorType::BeforeChildren:
+    case PositionAnchorType::AfterChildren:
+      return position;
+    case PositionAnchorType::BeforeAnchor:
+      if (anchorNode == nodeToBeRemoved)
+        return Position(mergedNode, mergedNode.length());
+      return position;
+    case PositionAnchorType::AfterAnchor:
+      if (anchorNode == nodeToBeRemoved)
+        return Position(mergedNode, mergedNode.length());
+      if (anchorNode == mergedNode)
+        return Position(mergedNode, oldLength);
+      return position;
+    case PositionAnchorType::OffsetInAnchor: {
+      const int offset = position.offsetInContainerNode();
+      if (anchorNode == nodeToBeRemoved)
+        return Position(mergedNode, oldLength + offset);
+      if (anchorNode == nodeToBeRemoved.parentNode() &&
+          offset == nodeToBeRemovedWithIndex.index()) {
+        return Position(mergedNode, oldLength);
+      }
+      return position;
+    }
+  }
+  NOTREACHED() << position;
+  return position;
+}
+
+void SelectionEditor::didMergeTextNodes(
+    const Text& mergedNode,
+    const NodeWithIndex& nodeToBeRemovedWithIndex,
+    unsigned oldLength) {
+  if (m_selection.isNone()) {
+    didFinishDOMMutation();
+    return;
+  }
+  const Position& newBase = updatePostionAfterAdoptingTextNodesMerged(
+      m_selection.m_base, mergedNode, nodeToBeRemovedWithIndex, oldLength);
+  const Position& newExtent = updatePostionAfterAdoptingTextNodesMerged(
+      m_selection.m_extent, mergedNode, nodeToBeRemovedWithIndex, oldLength);
+  didFinishTextChange(newBase, newExtent);
+}
+
+static Position updatePostionAfterAdoptingTextNodeSplit(
+    const Position& position,
+    const Text& oldNode) {
+  if (position.anchorNode() != &oldNode || !position.isOffsetInAnchor())
+    return position;
+  // See:
+  // http://www.w3.org/TR/DOM-Level-2-Traversal-Range/ranges.html#Level-2-Range-Mutation
+  DCHECK_GE(position.offsetInContainerNode(), 0);
+  unsigned positionOffset =
+      static_cast<unsigned>(position.offsetInContainerNode());
+  unsigned oldLength = oldNode.length();
+  if (positionOffset <= oldLength)
+    return position;
+  return Position(toText(oldNode.nextSibling()), positionOffset - oldLength);
+}
+
+void SelectionEditor::didSplitTextNode(const Text& oldNode) {
+  if (m_selection.isNone() || !oldNode.isConnected()) {
+    didFinishDOMMutation();
+    return;
+  }
+  const Position& newBase =
+      updatePostionAfterAdoptingTextNodeSplit(m_selection.m_base, oldNode);
+  const Position& newExtent =
+      updatePostionAfterAdoptingTextNodeSplit(m_selection.m_extent, oldNode);
+  didFinishTextChange(newBase, newExtent);
+}
+
+void SelectionEditor::didFinishTextChange(const Position& newBase,
+                                          const Position& newExtent) {
+  if (newBase != m_selection.m_base || newExtent != m_selection.m_extent) {
+    m_selection.m_base = newBase;
+    m_selection.m_extent = newExtent;
+    m_cachedVisibleSelectionInDOMTree = VisibleSelection();
+    m_cachedVisibleSelectionInFlatTree = VisibleSelectionInFlatTree();
+  }
+  didFinishDOMMutation();
+}
+
+void SelectionEditor::didFinishDOMMutation() {
+  m_domTreeVersion = document().domTreeVersion();
+#if ENABLE(ASSERT)
+  m_selection.m_domTreeVersion = m_domTreeVersion;
+#endif
+  m_cacheState = CacheState::DOMTreeIsChanged;
+  // TODO(yosin): Should we notify selection change?
+  m_selection.assertValidFor(document());
+}
+
+void SelectionEditor::nodeWillBeRemoved(Node& nodeToBeRemoved) {
+  if (m_selection.isNone())
+    return;
+  const Position oldBase = m_selection.m_base;
+  const Position oldExtent = m_selection.m_extent;
+  const Position& newBase =
+      computePositionForNodeRemoval(oldBase, nodeToBeRemoved);
+  const Position& newExtent =
+      computePositionForNodeRemoval(oldExtent, nodeToBeRemoved);
+  if (newBase == oldBase && newExtent == oldExtent)
+    return;
+  m_cacheState = CacheState::DOMTreeIsChanging;
+  m_selection = SelectionInDOMTree::Builder()
+                    .setBaseAndExtent(newBase, newExtent)
+                    .build();
+  m_cachedVisibleSelectionInDOMTree = VisibleSelection();
+  m_cachedVisibleSelectionInFlatTree = VisibleSelectionInFlatTree();
 }
 
 void SelectionEditor::documentAttached(Document* document) {
   DCHECK(document);
-  DCHECK(!m_document) << m_document;
-  m_document = document;
+  DCHECK(!lifecycleContext()) << lifecycleContext();
+  m_domTreeVersion = document->domTreeVersion();
+  m_styleVersion = static_cast<uint64_t>(-1);
+  clearVisibleSelection();
+  setContext(document);
 }
 
-void SelectionEditor::documentDetached(const Document& document) {
-  DCHECK_EQ(m_document, &document);
+void SelectionEditor::contextDestroyed(Document*) {
   dispose();
-  m_document = nullptr;
+  m_domTreeVersion = 0;
+  m_styleVersion = static_cast<uint64_t>(-1);
+  m_selection = SelectionInDOMTree();
+  m_cachedVisibleSelectionInDOMTree = VisibleSelection();
+  m_cachedVisibleSelectionInFlatTree = VisibleSelectionInFlatTree();
 }
 
 void SelectionEditor::resetLogicalRange() {
@@ -150,7 +452,7 @@ void SelectionEditor::setLogicalRange(Range* range) {
 Range* SelectionEditor::firstRange() const {
   if (m_logicalRange)
     return m_logicalRange->cloneRange();
-  return firstRangeOf(m_selection);
+  return firstRangeOf(computeVisibleSelectionInDOMTree());
 }
 
 bool SelectionEditor::shouldAlwaysUseDirectionalSelection() const {
@@ -158,18 +460,107 @@ bool SelectionEditor::shouldAlwaysUseDirectionalSelection() const {
 }
 
 void SelectionEditor::updateIfNeeded() {
-  DCHECK(m_selection.isValidFor(document())) << m_selection;
-  DCHECK(m_selectionInFlatTree.isValidFor(document())) << m_selection;
-  m_selection.updateIfNeeded();
-  m_selectionInFlatTree.updateIfNeeded();
+  // TODO(yosin): We should unify |SelectionEditor::updateIfNeeded()| and
+  // |updateCachedVisibleSelectionIfNeeded()|
+  updateCachedVisibleSelectionIfNeeded();
+}
+
+class SelectionEditor::CacheUpdateScope {
+  STACK_ALLOCATED();
+
+ public:
+  CacheUpdateScope(SelectionEditor*);
+  ~CacheUpdateScope();
+
+ private:
+  DEFINE_INLINE_TRACE() { visitor->trace(m_editor); }
+
+  Member<SelectionEditor> m_editor;
+  DISALLOW_COPY_AND_ASSIGN(CacheUpdateScope);
+};
+
+SelectionEditor::CacheUpdateScope::CacheUpdateScope(SelectionEditor* editor)
+    : m_editor(editor) {
+  m_editor->m_isUpdatingCachedSelection = true;
+}
+
+SelectionEditor::CacheUpdateScope::~CacheUpdateScope() {
+  m_editor->m_styleVersion = m_editor->document().styleVersion();
+  m_editor->m_cacheState = CacheState::VisibleSelectionMayBeValid;
+  m_editor->m_isUpdatingCachedSelection = false;
+}
+
+bool SelectionEditor::needsUpdateVisibleSelection() const {
+  DCHECK_EQ(m_domTreeVersion, document().domTreeVersion());
+  if (m_cacheState != CacheState::VisibleSelectionMayBeValid)
+    return true;
+  return m_styleVersion != document().styleVersion();
+}
+
+void SelectionEditor::updateCachedVisibleSelectionIfNeeded() {
+  DCHECK(!m_isUpdatingCachedSelection)
+      << "Recursive update should not be happened.";
+  m_selection.assertValidFor(document());
+
+  // We should use |DCHECK(!document().needsLayoutTreeUpdate())| but following
+  // tests are failed:
+  //  - media/track/css-cue-for-video-in-shadow-2.html
+  //  - media/track/css-cue-for-video-in-shadow.html
+  //  - media/track/cue-style-invalidation.html
+  //  - media/track/opera/track/webvtt/parsing/001.html
+  //  - media/track/text-track-selection-menu-add-track.html
+  //  - media/track/track-css-all-cues.html
+  //  - media/track/track-css-cue-lifetime.html [ Crash
+  // Note: Since we |FrameCaret::updateApperance()| is called from
+  // |FrameView::performPostLayoutTasks()|, we check lifecycle against
+  // |AfterPerformLayout| instead of |LayoutClean|.
+  DCHECK_GE(document().lifecycle().state(),
+            DocumentLifecycle::AfterPerformLayout);
+  if (!needsUpdateVisibleSelection())
+    return;
+
+  CacheUpdateScope updatingCache(this);
+  switch (m_cacheState) {
+    case CacheState::VisibleSelectionMayBeValid:
+      // TDOO(yosin): We should study why
+      // createVisibleSelection(m_cachedVisibleSelectionInDOMTree.asSelection())
+      // not
+      // work.
+      m_cachedVisibleSelectionInDOMTree.validate(
+          m_cachedVisibleSelectionInDOMTree.m_granularity);
+      m_cachedVisibleSelectionInFlatTree.validate(
+          m_cachedVisibleSelectionInFlatTree.m_granularity);
+      return;
+    case CacheState::DOMTreeIsChanged:
+    case CacheState::SelectionInDOMTreeIsSource: {
+      // TODO(yosin): We should get rid of |adjustSelectionInFlatTree| in
+      // |SelectionAdjuster|.
+      m_cachedVisibleSelectionInDOMTree = createVisibleSelection(m_selection);
+      m_cachedVisibleSelectionInFlatTree = createVisibleSelection(
+          SelectionInFlatTree::Builder()
+              .setBaseAndExtent(toPositionInFlatTree(m_selection.base()),
+                                toPositionInFlatTree(m_selection.extent()))
+              .setAffinity(m_selection.affinity())
+              .setHasTrailingWhitespace(m_selection.hasTrailingWhitespace())
+              .setGranularity(m_selection.granularity())
+              .setIsDirectional(m_selection.isDirectional())
+              .build());
+      return;
+    }
+    case CacheState::DOMTreeIsChanging:
+      NOTREACHED() << "We should not update selection during DOM mutation";
+      return;
+  }
+  NOTREACHED() << "We should handle " << m_cacheState;
 }
 
 DEFINE_TRACE(SelectionEditor) {
-  visitor->trace(m_document);
   visitor->trace(m_frame);
   visitor->trace(m_selection);
-  visitor->trace(m_selectionInFlatTree);
+  visitor->trace(m_cachedVisibleSelectionInDOMTree);
+  visitor->trace(m_cachedVisibleSelectionInFlatTree);
   visitor->trace(m_logicalRange);
+  SynchronousMutationObserver::trace(visitor);
 }
 
 }  // namespace blink