Potential bug on drawing video on SkCanvas

media/filters/skcanvas_video_renderer.h

Index: media/filters/skcanvas_video_renderer.h
diff --git a/media/filters/skcanvas_video_renderer.h b/media/filters/skcanvas_video_renderer.h
index 146e7cd16cec099ffc12b62019a4b1c466f59b63..1e81d316f56555034fffdbfef72325d252a6944b 100644
--- a/media/filters/skcanvas_video_renderer.h
+++ b/media/filters/skcanvas_video_renderer.h
@@ -7,6 +7,7 @@
 
 #include "base/memory/ref_counted.h"
 #include "base/time/time.h"
+#include "base/timer/timer.h"
 #include "media/base/media_export.h"
 #include "media/base/video_rotation.h"
 #include "third_party/skia/include/core/SkBitmap.h"
@@ -42,12 +43,24 @@ class MEDIA_EXPORT SkCanvasVideoRenderer {
   void Copy(const scoped_refptr<VideoFrame>&, SkCanvas* canvas);
 
  private:
-  VideoImageGenerator* generator_;
+  void ResetLastFrame();
+  void ResetAcceleratedLastFrame();
 
   // An RGB bitmap and corresponding timestamp of the previously converted
-  // video frame data.
+  // video frame data by software color space conversion.
   SkBitmap last_frame_;
   base::TimeDelta last_frame_timestamp_;
+  // If |last_frame_| is not used for a while, it's deleted to save memory.
+  base::DelayTimer<SkCanvasVideoRenderer> frame_deleting_timer_;
+
+  // This is a hardware accelerated copy of the frame generated by
+  // |accelerated_generator_|.
+  // It's used when |canvas| parameter in Paint() is Ganesh canvas.
+  // Note: all GrContext in SkCanvas instances are same.
+  SkBitmap accelerated_last_frame_;
+  VideoImageGenerator* accelerated_generator_;
+  base::TimeDelta accelerated_last_frame_timestamp_;
+  base::DelayTimer<SkCanvasVideoRenderer> accelerated_frame_deleting_timer_;
 
   DISALLOW_COPY_AND_ASSIGN(SkCanvasVideoRenderer);
 };