Add stable id to PaintImage.

media/renderers/skcanvas_video_renderer.h

Index: media/renderers/skcanvas_video_renderer.h
diff --git a/media/renderers/skcanvas_video_renderer.h b/media/renderers/skcanvas_video_renderer.h
index ae76c1d4664f357cd3c1ef08b61369941d14d332..3dd3ab7e10b0064c9d8d82b75f710247939dbaf2 100644
--- a/media/renderers/skcanvas_video_renderer.h
+++ b/media/renderers/skcanvas_video_renderer.h
@@ -15,6 +15,7 @@
 #include "base/timer/timer.h"
 #include "cc/paint/paint_canvas.h"
 #include "cc/paint/paint_flags.h"
+#include "cc/paint/paint_image.h"
 #include "media/base/media_export.h"
 #include "media/base/timestamp_constants.h"
 #include "media/base/video_frame.h"
@@ -170,6 +171,8 @@ class MEDIA_EXPORT SkCanvasVideoRenderer {
   base::TimeDelta last_timestamp_ = media::kNoTimestamp;
   // If |last_image_| is not used for a while, it's deleted to save memory.
   base::DelayTimer last_image_deleting_timer_;
+  // Stable paint image id to provide to draw image calls.
+  cc::PaintImage::Id renderer_stable_id_;
 
   // Used for DCHECKs to ensure method calls executed in the correct thread.
   base::ThreadChecker thread_checker_;