Move the Widget hierarchy to the Oilpan heap.

Source/core/frame/FrameView.h

 /*
    Copyright (C) 1997 Martin Jones (mjones@kde.org)
              (C) 1998 Waldo Bastian (bastian@kde.org)
              (C) 1998, 1999 Torben Weis (weis@kde.org)
              (C) 1999 Lars Knoll (knoll@kde.org)
              (C) 1999 Antti Koivisto (koivisto@kde.org)
    Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
 
    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
@@ skipping 39 matching lines @@
 class RenderBox;
 class RenderEmbeddedObject;
 class RenderObject;
 class RenderScrollbarPart;
 class RenderView;
 class RenderWidget;
 struct CompositedSelectionBound;
 
 typedef unsigned long long DOMTimeStamp;
 
-// FIXME: Oilpan: move Widget (and thereby FrameView) to the heap.
 class FrameView final : public ScrollView {
 public:
     friend class RenderView;
     friend class Internals;
 
-    static PassRefPtr<FrameView> create(LocalFrame*);
-    static PassRefPtr<FrameView> create(LocalFrame*, const IntSize& initialSize);
+    static PassRefPtrWillBeRawPtr<FrameView> create(LocalFrame*);
+    static PassRefPtrWillBeRawPtr<FrameView> create(LocalFrame*, const IntSize& initialSize);
 
     virtual ~FrameView();
 
     virtual HostWindow* hostWindow() const override;
 
     virtual void invalidateRect(const IntRect&) override;
     virtual void setFrameRect(const IntRect&) override;
 
     LocalFrame& frame() const
     {
         ASSERT(m_frame);
         return *m_frame;
     }
 
     Page* page() const;
 
     RenderView* renderView() const;
 
     virtual void setCanHaveScrollbars(bool) override;
 
-    virtual PassRefPtr<Scrollbar> createScrollbar(ScrollbarOrientation) override;
+    virtual PassRefPtrWillBeRawPtr<Scrollbar> createScrollbar(ScrollbarOrientation) override;
 
     virtual void setContentsSize(const IntSize&) override;
     IntPoint clampOffsetAtScale(const IntPoint& offset, float scale) const;
 
     void layout(bool allowSubtree = true);
     bool didFirstLayout() const;
     void scheduleRelayout();
     void scheduleRelayoutOfSubtree(RenderObject*);
     bool layoutPending() const;
     bool isInPerformLayout() const;
@@ skipping 119 matching lines @@
 
     void updateLayoutAndStyleForPainting();
     void updateLayoutAndStyleIfNeededRecursive();
 
     void invalidateTreeIfNeededRecursive();
 
     void incrementVisuallyNonEmptyCharacterCount(unsigned);
     void incrementVisuallyNonEmptyPixelCount(const IntSize&);
     void setIsVisuallyNonEmpty() { m_isVisuallyNonEmpty = true; }
     void enableAutoSizeMode(const IntSize& minSize, const IntSize& maxSize);
-    void disableAutoSizeMode() { m_autoSizeInfo.clear(); }
+    void disableAutoSizeMode() { disposeAutoSizeInfo(); }
 
     void forceLayout(bool allowSubtree = false);
     void forceLayoutForPagination(const FloatSize& pageSize, const FloatSize& originalPageSize, float maximumShrinkFactor);
 
     bool scrollToFragment(const KURL&);
     bool scrollToAnchor(const String&);
     void maintainScrollPositionAtAnchor(Node*);
     void scrollElementToRect(Element*, const IntRect&);
     void scrollContentsIfNeededRecursive();
 
@@ skipping 86 matching lines @@
     virtual void getTickmarks(Vector<IntRect>&) const override;
     virtual void scrollTo(const DoublePoint&) override;
     virtual IntRect scrollableAreaBoundingBox() const override;
     virtual bool scrollAnimatorEnabled() const override;
     virtual bool usesCompositedScrolling() const override;
     virtual GraphicsLayer* layerForScrolling() const override;
     virtual GraphicsLayer* layerForHorizontalScrollbar() const override;
     virtual GraphicsLayer* layerForVerticalScrollbar() const override;
     virtual GraphicsLayer* layerForScrollCorner() const override;
 
+    virtual void trace(Visitor*) override;
+
 protected:
     virtual bool scrollContentsFastPath(const IntSize& scrollDelta) override;
     virtual void scrollContentsSlowPath(const IntRect& updateRect) override;
 
     virtual bool isVerticalDocument() const override;
     virtual bool isFlippedDocument() const override;
 
     // Prevents creation of scrollbars. Used to prevent drawing two sets of
     // overlay scrollbars in the case of the pinch viewport.
     virtual bool scrollbarsDisabled() const override;
 
 private:
     explicit FrameView(LocalFrame*);
 
+    void dispose();
     void reset();
     void init();
 
     virtual void frameRectsChanged() override;
     virtual bool isFrameView() const override { return true; }
 
     friend class RenderWidget;
 
     bool contentsInCompositedLayer() const;
 
@@ skipping 51 matching lines @@
 
     virtual void updateScrollCorner() override;
 
     FrameView* parentFrameView() const;
 
     AXObjectCache* axObjectCache() const;
     void removeFromAXObjectCache();
 
     void setLayoutSizeInternal(const IntSize&);
 
+    void disposeAutoSizeInfo();
+
     bool paintInvalidationIsAllowed() const
     {
         return !isInPerformLayout() || canInvalidatePaintDuringPerformLayout();
     }
 
     static double s_currentFrameTimeStamp; // used for detecting decoded resource thrash in the cache
     static bool s_inPaintContents;
 
     LayoutSize m_size;
 
     typedef WillBeHeapHashSet<RefPtrWillBeMember<RenderEmbeddedObject> > EmbeddedObjectSet;
-    WillBePersistentHeapHashSet<RefPtrWillBeMember<RenderEmbeddedObject> > m_widgetUpdateSet;
+    WillBeHeapHashSet<RefPtrWillBeMember<RenderEmbeddedObject> > m_widgetUpdateSet;
 
     // FIXME: These are just "children" of the FrameView and should be RefPtr<Widget> instead.
-    WillBePersistentHeapHashSet<RefPtrWillBeMember<RenderWidget> > m_widgets;
+    WillBeHeapHashSet<RefPtrWillBeMember<RenderWidget> > m_widgets;
 
-    // Oilpan: the use of a persistent back reference 'emulates' the
-    // RefPtr-cycle that is kept between the two objects non-Oilpan.
+    // The RefPtr cycle between LocalFrame and FrameView is broken
+    // when a LocalFrame is detached by FrameLoader::detachFromParent().
+    // It clears the LocalFrame's m_view reference via setView(nullptr).
     //
-    // That cycle is broken when a LocalFrame is detached by
-    // FrameLoader::detachFromParent(), it then clears its
-    // FrameView's m_frame reference by calling setView(nullptr).
-    RefPtrWillBePersistent<LocalFrame> m_frame;
+    // For Oilpan, Member reference cycles pose no problem, but
+    // LocalFrame's FrameView is also cleared by setView(). This additionally
+    // triggers FrameView::dispose(), which performs the operations
+    // that cannot be delayed until finalization time.
+    RefPtrWillBeMember<LocalFrame> m_frame;
 
     bool m_doFullPaintInvalidation;
 
     bool m_canHaveScrollbars;
     unsigned m_slowRepaintObjectCount;
 
     bool m_hasPendingLayout;
     RenderObject* m_layoutSubtreeRoot;
 
     bool m_layoutSchedulingEnabled;
@@ skipping 22 matching lines @@
 
     bool m_wasScrolledByUser;
     bool m_inProgrammaticScroll;
     bool m_safeToPropagateScrollToParent;
 
     double m_lastPaintTime;
 
     bool m_isTrackingPaintInvalidations; // Used for testing.
     Vector<IntRect> m_trackedPaintInvalidationRects;
 
-    RefPtrWillBePersistent<Node> m_nodeToDraw;
+    RefPtrWillBeMember<Node> m_nodeToDraw;
     PaintBehavior m_paintBehavior;
     bool m_isPainting;
 
     unsigned m_visuallyNonEmptyCharacterCount;
     unsigned m_visuallyNonEmptyPixelCount;
     bool m_isVisuallyNonEmpty;
     bool m_firstVisuallyNonEmptyLayoutCallbackPending;
 
-    RefPtrWillBePersistent<Node> m_maintainScrollPositionAnchor;
+    RefPtrWillBeMember<Node> m_maintainScrollPositionAnchor;
 
     // Renderer to hold our custom scroll corner.
-    RawPtrWillBePersistent<RenderScrollbarPart> m_scrollCorner;
+    RawPtrWillBeMember<RenderScrollbarPart> m_scrollCorner;
 
     OwnPtr<ScrollableAreaSet> m_scrollableAreas;
     OwnPtr<ResizerAreaSet> m_resizerAreas;
     OwnPtr<ViewportConstrainedObjectSet> m_viewportConstrainedObjects;
-    OwnPtr<FrameViewAutoSizeInfo> m_autoSizeInfo;
+    OwnPtrWillBeMember<FrameViewAutoSizeInfo> m_autoSizeInfo;
 
     float m_visibleContentScaleFactor;
     IntSize m_inputEventsOffsetForEmulation;
     float m_inputEventsScaleFactorForEmulation;
 
     IntSize m_layoutSize;
     bool m_layoutSizeFixedToFrameSize;
 
     Timer<FrameView> m_didScrollTimer;
 
     Vector<IntRect> m_tickmarks;
 
+    float m_topControlsViewportAdjustment;
     bool m_needsUpdateWidgetPositions;
-    float m_topControlsViewportAdjustment;
+
+#if ENABLE(OILPAN) && ENABLE(ASSERT)
+    // Verified when finalizing.
+    bool m_hasBeenDisposed;
+#endif
 };
 
 inline void FrameView::incrementVisuallyNonEmptyCharacterCount(unsigned count)
 {
     if (m_isVisuallyNonEmpty)
         return;
     m_visuallyNonEmptyCharacterCount += count;
     // Use a threshold value to prevent very small amounts of visible content from triggering didFirstVisuallyNonEmptyLayout.
     // The first few hundred characters rarely contain the interesting content of the page.
     static const unsigned visualCharacterThreshold = 200;
     if (m_visuallyNonEmptyCharacterCount > visualCharacterThreshold)
         setIsVisuallyNonEmpty();
 }
 
 inline void FrameView::incrementVisuallyNonEmptyPixelCount(const IntSize& size)
 {
     if (m_isVisuallyNonEmpty)
         return;
     m_visuallyNonEmptyPixelCount += size.width() * size.height();
     // Use a threshold value to prevent very small amounts of visible content from triggering didFirstVisuallyNonEmptyLayout
     static const unsigned visualPixelThreshold = 32 * 32;
     if (m_visuallyNonEmptyPixelCount > visualPixelThreshold)
         setIsVisuallyNonEmpty();
 }
 
 DEFINE_TYPE_CASTS(FrameView, Widget, widget, widget->isFrameView(), widget.isFrameView());
 
 class AllowPaintInvalidationScope {
+    STACK_ALLOCATED();
 public:
     explicit AllowPaintInvalidationScope(FrameView* view)
         : m_view(view)
         , m_originalValue(view ? view->canInvalidatePaintDuringPerformLayout() : false)
     {
         if (!m_view)
             return;
 
         m_view->setCanInvalidatePaintDuringPerformLayout(true);
     }
 
     ~AllowPaintInvalidationScope()
     {
         if (!m_view)
             return;
 
         m_view->setCanInvalidatePaintDuringPerformLayout(m_originalValue);
     }
+
 private:
-    FrameView* m_view;
+    RawPtrWillBeMember<FrameView> m_view;
     bool m_originalValue;
 };
 
 } // namespace blink
 
 #endif // FrameView_h