[Oilpan] Move ScrollAnimators onto oilpan heap

third_party/WebKit/Source/platform/scroll/ScrollAnimatorBase.h

 /*
  * Copyright (c) 2010, Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 26 matching lines @@
 #include "platform/heap/Handle.h"
 #include "platform/scroll/ScrollTypes.h"
 #include "wtf/Forward.h"
 
 namespace blink {
 
 class FloatPoint;
 class ScrollableArea;
 class Scrollbar;
 
-class PLATFORM_EXPORT ScrollAnimatorBase {
+class PLATFORM_EXPORT ScrollAnimatorBase : public GarbageCollectedFinalized<ScrollAnimatorBase> {
 public:
-    static PassOwnPtr<ScrollAnimatorBase> create(ScrollableArea*);
+    static ScrollAnimatorBase* create(ScrollableArea*);
 
     virtual ~ScrollAnimatorBase();
+    virtual void cleanup() { }
 
     // Computes a scroll destination for the given parameters.  The returned
     // ScrollResultOneDimensional will have didScroll set to false if already at
     // the destination.  Otherwise, starts scrolling towards the destination and
     // didScroll is true.  Scrolling may be immediate or animated. The base
     // class implementation always scrolls immediately, never animates.
     virtual ScrollResultOneDimensional userScroll(ScrollbarOrientation, ScrollGranularity, float step, float delta);
 
     virtual void scrollToOffsetWithoutAnimation(const FloatPoint&);
 
@@ skipping 30 matching lines @@
     virtual void didAddVerticalScrollbar(Scrollbar*) { }
     virtual void willRemoveVerticalScrollbar(Scrollbar*) { }
     virtual void didAddHorizontalScrollbar(Scrollbar*) { }
     virtual void willRemoveHorizontalScrollbar(Scrollbar*) { }
 
     virtual bool shouldScrollbarParticipateInHitTesting(Scrollbar*) { return true; }
 
     virtual void notifyContentAreaScrolled(const FloatSize&) { }
 
     virtual bool setScrollbarsVisibleForTesting(bool) { return false; }
+
+    DECLARE_VIRTUAL_TRACE();
+
 protected:
     explicit ScrollAnimatorBase(ScrollableArea*);
 
     virtual void notifyPositionChanged();
 
-    GC_PLUGIN_IGNORE("509911")
-    ScrollableArea* m_scrollableArea;
+    RawPtrWillBeMember<ScrollableArea> m_scrollableArea;

[haraken, 2015/12/03 05:34:35]

In non-oilpan, this raw pointer has a risk of becoming a stale pointer (if the
ScrollableArea gets destructed before the next GC collects the
ScrollAnimatorBase).

Sorry about getting you back and forth, but I'd suggest making ScrollableArea
NoBaseWillBeGarbageCollected (not GarbageCollected). Then the risk will be gone.
Also you don't need to call cleanup() only in non-oilpan when the ScrollableArea
gets destructed.

[peria, 2015/12/03 09:24:25]

Done.

     float m_currentPosX; // We avoid using a FloatPoint in order to reduce
     float m_currentPosY; // subclass code complexity.
 
 private:
     float clampScrollPosition(ScrollbarOrientation, float);
 };
 
 } // namespace blink
 
 #endif // ScrollAnimatorBase_h