Treat calls to CanvasRenderingContext2D.clearRect as operations that clear the canvas

Source/platform/graphics/GraphicsContextRecorder.cpp

 /*
  * Copyright (C) 2013 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 39 matching lines @@
 
 GraphicsContext* GraphicsContextRecorder::record(const IntSize& size, bool isCertainlyOpaque)
 {
     ASSERT(!m_picture);
     ASSERT(!m_recorder);
     ASSERT(!m_context);
     m_isCertainlyOpaque = isCertainlyOpaque;
     m_recorder = adoptPtr(new SkPictureRecorder);
     SkCanvas* canvas = m_recorder->beginRecording(size.width(), size.height(), 0, 0);
     m_context = adoptPtr(new GraphicsContext(canvas));
-    m_context->setTrackOpaqueRegion(isCertainlyOpaque);
+    m_context->setRegionTrackingMode(isCertainlyOpaque ? GraphicsContext::RegionTrackingOpaque : GraphicsContext::RegionTrackingDisabled);
     m_context->setCertainlyOpaque(isCertainlyOpaque);
     return m_context.get();
 }
 
 PassRefPtr<GraphicsContextSnapshot> GraphicsContextRecorder::stop()
 {
     m_context.clear();
     m_picture = adoptRef(m_recorder->endRecording());
     m_recorder.clear();
     return adoptRef(new GraphicsContextSnapshot(m_picture.release(), m_isCertainlyOpaque));
@@ skipping 74 matching lines @@
 }
 
 PassRefPtr<JSONArray> GraphicsContextSnapshot::snapshotCommandLog() const
 {
     LoggingCanvas canvas(m_picture->width(), m_picture->height());
     m_picture->draw(&canvas);
     return canvas.log();
 }
 
 }