Eliminate deferral overhead with canvas to canvas draws

Source/platform/graphics/UnacceleratedImageBufferSurface.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 34 matching lines @@
     SkImageInfo info = SkImageInfo::MakeN32(size.width(), size.height(), alphaType);
     SkSurfaceProps disableLCDProps(0, kUnknown_SkPixelGeometry);
     m_surface = adoptRef(SkSurface::NewRaster(info, Opaque == opacityMode ? 0 : &disableLCDProps));
 
     if (m_surface)
         clear();
 }
 
 UnacceleratedImageBufferSurface::~UnacceleratedImageBufferSurface() { }
 
-SkCanvas* UnacceleratedImageBufferSurface::immediateCanvas()
+SkCanvas* UnacceleratedImageBufferSurface::canvas()
 {
     return m_surface->getCanvas();
 }
 
 const SkBitmap& UnacceleratedImageBufferSurface::deprecatedBitmapForOverwrite()
 {
     m_surface->notifyContentWillChange(SkSurface::kDiscard_ContentChangeMode);
     return m_surface->getCanvas()->getDevice()->accessBitmap(false);
 }
 
 bool UnacceleratedImageBufferSurface::isValid() const
 {
     return m_surface;
 }
 
 PassRefPtr<SkImage> UnacceleratedImageBufferSurface::newImageSnapshot()
 {
     return adoptRef(m_surface->newImageSnapshot());
 }
 
 } // namespace blink