Unify and provide one IsGarbageCollectedType<T> implementation.

third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@gmail.com>
  *   Randall Jesup <rjesup@wgate.com>
@@ skipping 62 matching lines @@
 #include "platform/PlatformMouseEvent.h"
 #include "platform/graphics/CompositorMutableProperties.h"
 #include "platform/graphics/GraphicsLayer.h"
 #include "platform/graphics/paint/DrawingRecorder.h"
 #include "platform/scroll/ScrollAnimatorBase.h"
 #include "platform/scroll/ScrollbarTheme.h"
 #include "public/platform/Platform.h"
 
 namespace blink {
 
+PaintLayerScrollableAreaRareData::PaintLayerScrollableAreaRareData()
+{
+}
+
 const int ResizerControlExpandRatioForTouch = 2;
 
 PaintLayerScrollableArea::PaintLayerScrollableArea(PaintLayer& layer)
     : m_layer(layer)
     , m_inResizeMode(false)
     , m_scrollsOverflow(false)
     , m_inOverflowRelayout(false)
     , m_nextTopmostScrollChild(0)
     , m_topmostScrollChild(0)
     , m_needsCompositedScrolling(false)
@@ skipping 1515 matching lines @@
 }
 
 DEFINE_TRACE(PaintLayerScrollableArea::ScrollbarManager)
 {
     visitor->trace(m_scrollableArea);
     visitor->trace(m_hBar);
     visitor->trace(m_vBar);
 }
 
 } // namespace blink