Oilpan: move a page's UndoStack to the heap.

Avoids its unnecessary persistents by doing so.

R=tkent@chromium.org
BUG=357163

Review URL: https://codereview.chromium.org/333313002

git-svn-id: svn://svn.chromium.org/blink/trunk@176217 bbb929c8-8fbe-4397-9dbb-9b2b20218538

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

@@ -45,13 +45,11 @@ UndoStack::UndoStack()
 {
 }
 
-UndoStack::~UndoStack()
-{
-}
+DEFINE_EMPTY_DESTRUCTOR_WILL_BE_REMOVED(UndoStack)
 
-PassOwnPtr<UndoStack> UndoStack::create()
+PassOwnPtrWillBeRawPtr<UndoStack> UndoStack::create()
 {
-    return adoptPtr(new UndoStack());
+    return adoptPtrWillBeNoop(new UndoStack());
 }
 
 void UndoStack::registerUndoStep(PassRefPtrWillBeRawPtr<UndoStep> step)
@@ -75,7 +73,7 @@ void UndoStack::didUnloadFrame(const LocalFrame& frame)
     filterOutUndoSteps(m_redoStack, frame);
 }
 
-void UndoStack::filterOutUndoSteps(WillBePersistentUndoStepStack& stack, const LocalFrame& frame)
+void UndoStack::filterOutUndoSteps(UndoStepStack& stack, const LocalFrame& frame)
 {
     UndoStepStack newStack;
     while (!stack.isEmpty()) {
@@ -122,4 +120,10 @@ void UndoStack::redo()
     }
 }
 
+void UndoStack::trace(Visitor* visitor)
+{
+    visitor->trace(m_undoStack);
+    visitor->trace(m_redoStack);
+}
+
 } // namesace WebCore

third_party/WebKit/Source/core/editing/UndoStack.h

@@ -40,11 +40,10 @@ namespace WebCore {
 class LocalFrame;
 class UndoStep;
 
-class UndoStack {
+class UndoStack FINAL : public NoBaseWillBeGarbageCollected<UndoStack> {
+    DECLARE_EMPTY_DESTRUCTOR_WILL_BE_REMOVED(UndoStack)
 public:
-    static PassOwnPtr<UndoStack> create();
-
-    ~UndoStack();
+    static PassOwnPtrWillBeRawPtr<UndoStack> create();
 
     void registerUndoStep(PassRefPtrWillBeRawPtr<UndoStep>);
     void registerRedoStep(PassRefPtrWillBeRawPtr<UndoStep>);
@@ -54,17 +53,18 @@ public:
     void undo();
     void redo();
 
+    void trace(Visitor*);
+
 private:
     UndoStack();
 
     typedef WillBeHeapDeque<RefPtrWillBeMember<UndoStep> > UndoStepStack;
-    typedef WillBePersistentHeapDeque<RefPtrWillBeMember<UndoStep> > WillBePersistentUndoStepStack;
 
-    void filterOutUndoSteps(WillBePersistentUndoStepStack&, const LocalFrame&);
+    void filterOutUndoSteps(UndoStepStack&, const LocalFrame&);
 
     bool m_inRedo;
-    WillBePersistentUndoStepStack m_undoStack;
-    WillBePersistentUndoStepStack m_redoStack;
+    UndoStepStack m_undoStack;
+    UndoStepStack m_redoStack;
 };
 
 } // namespace WebCore

third_party/WebKit/Source/core/page/Page.cpp

@@ -594,6 +594,7 @@ void Page::trace(Visitor* visitor)
     visitor->trace(m_dragCaretController);
     visitor->trace(m_dragController);
     visitor->trace(m_pointerLockController);
+    visitor->trace(m_undoStack);
     visitor->trace(m_validationMessageClient);
     visitor->trace(m_multisamplingChangedObservers);
     visitor->trace(m_frameHost);

third_party/WebKit/Source/core/page/Page.h

@@ -257,7 +257,7 @@ private:
     const OwnPtr<InspectorController> m_inspectorController;
     const OwnPtrWillBeMember<PointerLockController> m_pointerLockController;
     OwnPtr<ScrollingCoordinator> m_scrollingCoordinator;
-    const OwnPtr<UndoStack> m_undoStack;
+    const OwnPtrWillBeMember<UndoStack> m_undoStack;
 
     RefPtr<Frame> m_mainFrame;