Fix MultiPictureDraw issues with GpuImageDecodeController

cc/playback/raster_source.h

Index: cc/playback/raster_source.h
diff --git a/cc/playback/raster_source.h b/cc/playback/raster_source.h
index c50c4a0f626a4bdf2e38864d3d910ccf65822b0e..d49c6c29e0f51699d45f23c8c4c14fdd950482d2 100644
--- a/cc/playback/raster_source.h
+++ b/cc/playback/raster_source.h
@@ -118,6 +118,15 @@ class CC_EXPORT RasterSource : public base::RefCountedThreadSafe<RasterSource> {
   // of the raster source, since the raster source will access it during raster.
   void SetImageDecodeController(ImageDecodeController* image_decode_controller);
 
+  // Returns the ImageDecodeController, currently only used by
+  // GpuRasterBufferProvider in order

[vmpstr, 2016/07/14 21:41:54]

nit: can you reformat the comment?

[ericrk, 2016/07/14 22:04:20]

Done.

+  // to create its own ImageHijackCanvas. Because of the MultiPictureDraw
+  // approach used by
+  // GPU raster, it does not integrate well with the use of the
+  // ImageHijackCanvas internal
+  // to this class. See gpu_raster_buffer_provider.cc for more information.

[vmpstr, 2016/07/14 21:41:54]

Can you file a bug and 

TODO(crbug.com/######): Redesign this to avoid exposing ImageDecodeController
from the raster source

[ericrk, 2016/07/14 22:04:20]

Done.

+  ImageDecodeController* GetImageDecodeController() const;
+
  protected:
   friend class base::RefCountedThreadSafe<RasterSource>;