Initial implementation of display list backed 2D canvases

Source/platform/graphics/ImageBufferSurface.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 17 matching lines @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "config.h"
 
 #include "platform/graphics/ImageBufferSurface.h"
 
 #include "platform/graphics/ImageBuffer.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "third_party/skia/include/core/SkDevice.h"
+#include "third_party/skia/include/core/SkPicture.h"
 
 namespace blink {
 
 ImageBufferSurface::ImageBufferSurface(const IntSize& size, OpacityMode opacityMode)
     : m_opacityMode(opacityMode)
     , m_size(size)
 {
     setIsHidden(false);
 }
 
+PassRefPtr<SkPicture> ImageBufferSurface::getPicture()
+{
+    return nullptr;
+}
+
 void ImageBufferSurface::clear()
 {
     // Clear the background transparent or opaque, as required. It would be nice if this wasn't
     // required, but the canvas is currently filled with the magic transparency
     // color. Can we have another way to manage this?
     if (isValid()) {
         if (m_opacityMode == Opaque)
             canvas()->drawARGB(255, 0, 0, 0, SkXfermode::kSrc_Mode);
         else
             canvas()->drawARGB(0, 0, 0, 0, SkXfermode::kClear_Mode);
+        didClearCanvas();
     }
 }
 
-const SkBitmap& ImageBufferSurface::bitmap() const
+const SkBitmap& ImageBufferSurface::bitmap()
 {
     ASSERT(canvas());
+    willReadback();
     return canvas()->getTopDevice()->accessBitmap(false);
 }
 
 const SkBitmap& ImageBufferSurface::cachedBitmap() const
 {
     DEFINE_STATIC_LOCAL(SkBitmap, nullBitmap, ());
     return nullBitmap;
 }
 
 } // namespace blink