Move the Widget hierarchy to the Oilpan heap.

Source/platform/scroll/ScrollView.h

 /*
  * Copyright (C) 2004, 2006, 2007, 2008 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Holger Hans Peter Freyther
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 12 matching lines @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef ScrollView_h
 #define ScrollView_h
 
 #include "platform/PlatformExport.h"
 #include "platform/Widget.h"
 #include "platform/geometry/IntRect.h"
+#include "platform/heap/Handle.h"
 #include "platform/scroll/ScrollTypes.h"
 #include "platform/scroll/ScrollableArea.h"
 #include "platform/scroll/Scrollbar.h"
 
 #include "wtf/HashSet.h"
 #include "wtf/TemporaryChange.h"
 
 namespace blink {
 
 class Scrollbar;
 
 class PLATFORM_EXPORT ScrollView : public Widget, public ScrollableArea {
 public:
     virtual ~ScrollView();
 
+    virtual void trace(Visitor*) OVERRIDE;
+
     // ScrollableArea functions.
     virtual int scrollSize(ScrollbarOrientation) const override;
     virtual void setScrollOffset(const IntPoint&) override;
     virtual void setScrollOffset(const DoublePoint&) override;
     virtual bool isScrollCornerVisible() const override;
     virtual void scrollbarStyleChanged() override;
     virtual bool userInputScrollable(ScrollbarOrientation) const override;
     virtual bool shouldPlaceVerticalScrollbarOnLeft() const override;
 
     virtual void notifyPageThatContentAreaWillPaint() const;
 
     // The window that hosts the ScrollView. The ScrollView will communicate scrolls and repaints to the
     // host window in the window's coordinate space.
     virtual HostWindow* hostWindow() const = 0;
 
     // Returns a clip rect in host window coordinates. Used to clip the blit on a scroll.
     virtual IntRect windowClipRect(IncludeScrollbarsInRect = ExcludeScrollbars) const = 0;
 
+    typedef WillBeHeapHashSet<RefPtrWillBeMember<Widget> > ChildrenWidgetSet;
+
     // Functions for child manipulation and inspection.
-    const HashSet<RefPtr<Widget> >* children() const { return &m_children; }
-    virtual void addChild(PassRefPtr<Widget>);
+    const ChildrenWidgetSet* children() const { return &m_children; }
+    virtual void addChild(PassRefPtrWillBeRawPtr<Widget>);
     virtual void removeChild(Widget*);
 
     // If the scroll view does not use a native widget, then it will have cross-platform Scrollbars. These functions
     // can be used to obtain those scrollbars.
     virtual Scrollbar* horizontalScrollbar() const override { return m_horizontalScrollbar.get(); }
     virtual Scrollbar* verticalScrollbar() const override { return m_verticalScrollbar.get(); }
     virtual bool isScrollViewScrollbar(const Widget* child) const override { return horizontalScrollbar() == child || verticalScrollbar() == child; }
 
     void positionScrollbarLayers();
 
@@ skipping 18 matching lines @@
 
     virtual void setCanHaveScrollbars(bool);
     bool canHaveScrollbars() const { return horizontalScrollbarMode() != ScrollbarAlwaysOff || verticalScrollbarMode() != ScrollbarAlwaysOff; }
 
     // By default, paint events are clipped to the visible area.  If set to
     // false, paint events are no longer clipped.
     bool clipsPaintInvalidations() const { return m_clipsRepaints; }
     void setClipsRepaints(bool);
 
     // Overridden by FrameView to create custom CSS scrollbars if applicable.
-    virtual PassRefPtr<Scrollbar> createScrollbar(ScrollbarOrientation);
+    virtual PassRefPtrWillBeRawPtr<Scrollbar> createScrollbar(ScrollbarOrientation);
 
     // The visible content rect has a location that is the scrolled offset of the document. The width and height are the viewport width
     // and height. By default the scrollbars themselves are excluded from this rectangle, but an optional boolean argument allows them to be
     // included.
     virtual IntRect visibleContentRect(IncludeScrollbarsInRect = ExcludeScrollbars) const override;
     IntSize visibleSize() const { return visibleContentRect().size(); }
 
     // visibleContentRect().size() is computed from unscaledVisibleContentSize() divided by the value of visibleContentScaleFactor.
     // For the main frame, visibleContentScaleFactor is equal to the page's pageScaleFactor; it's 1 otherwise.
     IntSize unscaledVisibleContentSize(IncludeScrollbarsInRect = ExcludeScrollbars) const;
@@ skipping 188 matching lines @@
     virtual bool scrollbarsDisabled() const { return false; }
 
 private:
     bool adjustScrollbarExistence(ComputeScrollbarExistenceOption = FirstPass);
     void adjustScrollbarOpacity();
     // FIXME(bokan): setScrollOffset, setScrollPosition, scrollTo, scrollToOffsetWithoutAnimation,
     // notifyScrollPositionChanged...there's too many ways to scroll this class. This needs
     // some cleanup.
     void setScrollOffsetFromUpdateScrollbars(const IntSize&);
 
-    RefPtr<Scrollbar> m_horizontalScrollbar;
-    RefPtr<Scrollbar> m_verticalScrollbar;
+    RefPtrWillBeMember<Scrollbar> m_horizontalScrollbar;
+    RefPtrWillBeMember<Scrollbar> m_verticalScrollbar;
     ScrollbarMode m_horizontalScrollbarMode;
     ScrollbarMode m_verticalScrollbarMode;
 
     bool m_horizontalScrollbarLock;
     bool m_verticalScrollbarLock;
 
-    HashSet<RefPtr<Widget> > m_children;
+    ChildrenWidgetSet m_children;
 
     DoubleSize m_pendingScrollDelta;
     DoublePoint m_scrollPosition;
     DoublePoint m_cachedScrollPosition;
     IntSize m_contentsSize;
 
     int m_scrollbarsAvoidingResizer;
     bool m_scrollbarsSuppressed;
 
     bool m_inUpdateScrollbars;
@@ skipping 10 matching lines @@
 
     void calculateOverhangAreasForPainting(IntRect& horizontalOverhangRect, IntRect& verticalOverhangRect);
     void updateOverhangAreas();
 }; // class ScrollView
 
 DEFINE_TYPE_CASTS(ScrollView, Widget, widget, widget->isScrollView(), widget.isScrollView());
 
 } // namespace blink
 
 #endif // ScrollView_h