Dispose temporary and not-cached Range in DOMSelection

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

Index: third_party/WebKit/Source/core/editing/DOMSelection.cpp
diff --git a/third_party/WebKit/Source/core/editing/DOMSelection.cpp b/third_party/WebKit/Source/core/editing/DOMSelection.cpp
index d473161afba0f1e496fda0842d1b9f6079b6c2fb..aa15eb366788d22e532b65d8de49279b9a4a7dda 100644
--- a/third_party/WebKit/Source/core/editing/DOMSelection.cpp
+++ b/third_party/WebKit/Source/core/editing/DOMSelection.cpp
@@ -125,8 +125,25 @@ static Position extentPosition(const VisibleSelection& selection) {
   return selection.extent().parentAnchoredEquivalent();
 }
 
+class ScopedRange {

[yosin_UTC9, 2017/03/30 08:58:17]

Please introduce a function acts like primaryRangeOrNull() but returns
EphemeralRange, e.g.

Optinal<EphemeralRange> compurePrimaryEphemeralRange().

We don't want to introduce |ScopedRange| anywhere. We discussed introducing it
on Jun 2014 when
[1] was filed.


[1] http://crbug.com/388681 Avoid registering temporary Range object for
updating on the Document

+  STACK_ALLOCATED();
+
+ public:
+  ScopedRange(Range* range, bool dispose)
+      : m_range(range), m_dispose(dispose) {}
+  ~ScopedRange() {
+    if (m_dispose)
+      m_range->dispose();
+  }
+
+ private:
+  Member<Range> m_range;
+  bool m_dispose;
+};
+
 Node* DOMSelection::anchorNode() const {
   if (Range* range = primaryRangeOrNull()) {
+    ScopedRange scope(range, !isSelectionOfDocument());
     if (!frame() || isBaseFirstInSelection())
       return range->startContainer();
     return range->endContainer();
@@ -136,6 +153,7 @@ Node* DOMSelection::anchorNode() const {
 
 unsigned DOMSelection::anchorOffset() const {
   if (Range* range = primaryRangeOrNull()) {
+    ScopedRange scope(range, !isSelectionOfDocument());
     if (!frame() || isBaseFirstInSelection())
       return range->startOffset();
     return range->endOffset();
@@ -145,6 +163,7 @@ unsigned DOMSelection::anchorOffset() const {
 
 Node* DOMSelection::focusNode() const {
   if (Range* range = primaryRangeOrNull()) {
+    ScopedRange scope(range, !isSelectionOfDocument());
     if (!frame() || isBaseFirstInSelection())
       return range->endContainer();
     return range->startContainer();
@@ -154,6 +173,7 @@ Node* DOMSelection::focusNode() const {
 
 unsigned DOMSelection::focusOffset() const {
   if (Range* range = primaryRangeOrNull()) {
+    ScopedRange scope(range, !isSelectionOfDocument());
     if (!frame() || isBaseFirstInSelection())
       return range->endOffset();
     return range->startOffset();
@@ -589,7 +609,9 @@ void DOMSelection::removeRange(Range* range) {
   DCHECK(range);
   if (!isAvailable())
     return;
-  if (range == primaryRangeOrNull())
+  Range* originalRange = primaryRangeOrNull();
+  ScopedRange scope(originalRange, !isSelectionOfDocument());
+  if (range == originalRange)
     frame()->selection().clear();
 }
 
@@ -631,6 +653,7 @@ void DOMSelection::addRange(Range* newRange) {
 
   Range* originalRange = primaryRangeOrNull();
   DCHECK(originalRange);
+  ScopedRange scope(originalRange, !isSelectionOfDocument());
 
   if (originalRange->startContainer()->treeScope() !=
       newRange->startContainer()->treeScope()) {