[Media] Record time it takes to start rendering audio and video

media/renderers/audio_renderer_impl.h

Index: media/renderers/audio_renderer_impl.h
diff --git a/media/renderers/audio_renderer_impl.h b/media/renderers/audio_renderer_impl.h
index f7915d31a607bdc512ac96704a1ddc7085c8d5cf..2b10ac695b26779a926b545aa101998ad83e005e 100644
--- a/media/renderers/audio_renderer_impl.h
+++ b/media/renderers/audio_renderer_impl.h
@@ -286,6 +286,10 @@ class MEDIA_EXPORT AudioRendererImpl
   // being used to adjust for lost time between the last call.
   base::TimeTicks stop_rendering_time_;
 
+  // Set when SetMediaTime() is called and used to record the amount of time it
+  // took from seeking to rendering the first frame.
+  base::TimeTicks start_rendering_time_;
+
   // Set upon receipt of the first decoded buffer after a StartPlayingFrom().
   // Used to determine how long to delay playback.
   base::TimeDelta first_packet_timestamp_;