Oilpan: improve ScrollableArea handling.

Source/platform/scroll/ScrollableArea.cpp

 /*
  * Copyright (c) 2010, Google Inc. All rights reserved.
  * Copyright (C) 2008, 2011 Apple 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.
@@ skipping 34 matching lines @@
 #include "platform/TraceEvent.h"
 
 static const int kPixelsPerLineStep = 40;
 static const float kMinFractionToStepWhenPaging = 0.875f;
 
 namespace blink {
 
 struct SameSizeAsScrollableArea {
     virtual ~SameSizeAsScrollableArea();
     IntRect scrollbarDamage[2];
+#if ENABLE(ASSERT) && ENABLE(OILPAN)
+    VerifyEagerFinalization verifyEager;

[haraken, 2015/06/30 10:30:36]

Nit: This could be removed if we use a pre-finalizer...

+#endif
     void* pointer;
     unsigned bitfields : 16;
     IntPoint origin;
 };
 
 static_assert(sizeof(ScrollableArea) == sizeof(SameSizeAsScrollableArea), "ScrollableArea should stay small");
 
 int ScrollableArea::pixelsPerLineStep()
 {
     return kPixelsPerLineStep;
@@ skipping 14 matching lines @@
     : m_inLiveResize(false)
     , m_scrollbarOverlayStyle(ScrollbarOverlayStyleDefault)
     , m_scrollOriginChanged(false)
 {
 }
 
 ScrollableArea::~ScrollableArea()
 {
 }
 
+void ScrollableArea::clearScrollAnimators()
+{
+    m_animators.clear();
+}
+
 ScrollAnimator* ScrollableArea::scrollAnimator() const
 {
     if (!m_animators)
         m_animators = adoptPtr(new ScrollableAreaAnimators);
 
     if (!m_animators->scrollAnimator)
         m_animators->scrollAnimator = ScrollAnimator::create(const_cast<ScrollableArea*>(this));
 
     return m_animators->scrollAnimator.get();
 }
@@ skipping 503 matching lines @@
         verticalScrollbarWidth = !verticalBar->isOverlayScrollbar() ? verticalBar->width() : 0;
     if (Scrollbar* horizontalBar = horizontalScrollbar())
         horizontalScrollbarHeight = !horizontalBar->isOverlayScrollbar() ? horizontalBar->height() : 0;
 
     return IntSize(std::max(0, size.width() - verticalScrollbarWidth),
         std::max(0, size.height() - horizontalScrollbarHeight));
 
 }
 
 } // namespace blink