cc: Add image decode control in the compositor.

cc/playback/display_list_raster_source.h

Index: cc/playback/display_list_raster_source.h
diff --git a/cc/playback/display_list_raster_source.h b/cc/playback/display_list_raster_source.h
index 8c06c8d68637dc5175b18bf8d93ee57ace1a8bc9..5c1e45fd7ba45a52a29b76557499a0d3625e19a5 100644
--- a/cc/playback/display_list_raster_source.h
+++ b/cc/playback/display_list_raster_source.h
@@ -18,6 +18,7 @@
 namespace cc {
 class DisplayItemList;
 class DrawImage;
+class ImageDecodeController;
 
 class CC_EXPORT DisplayListRasterSource
     : public base::RefCountedThreadSafe<DisplayListRasterSource> {
@@ -106,6 +107,10 @@ class CC_EXPORT DisplayListRasterSource
 
   scoped_refptr<DisplayListRasterSource> CreateCloneWithoutLCDText() const;
 
+  // Image decode controller should be set once. Its lifetime has to exceed that
+  // of the raster source, since the raster source will access it during raster.
+  void SetImageDecodeController(ImageDecodeController* image_decode_controller);
+
  protected:
   friend class base::RefCountedThreadSafe<DisplayListRasterSource>;
 
@@ -132,6 +137,8 @@ class CC_EXPORT DisplayListRasterSource
   // threads with multi-threaded Ganesh.  Make this const or remove it.
   bool should_attempt_to_use_distance_field_text_;
 
+  ImageDecodeController* image_decode_controller_;

[ericrk, 2015/12/04 00:50:46]

Given all the warnings above re threading, can you add a comment here indicating
why this is threadsafe (I'm assuming it is only set once before any threaded
work begins?)

+
  private:
   // Called when analyzing a tile. We can use AnalysisCanvas as
   // SkPicture::AbortCallback, which allows us to early out from analysis.