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

media/base/renderer_client.h

Index: media/base/renderer_client.h
diff --git a/media/base/renderer_client.h b/media/base/renderer_client.h
index 402c31b2e877db6a9a2b292392df282d9bb5efc9..8e1c30a198badff1fe3e9d6fb4ae403c4e04e142 100644
--- a/media/base/renderer_client.h
+++ b/media/base/renderer_client.h
@@ -41,6 +41,9 @@ class RendererClient {
   // Executed when video metadata is first read, and whenever it changes.
   // Only used when we are using a URL demuxer (e.g. for MediaPlayerRenderer).
   virtual void OnDurationChange(base::TimeDelta duration) = 0;
+
+  // Executed when the first frame is rendered after the playback restart.
+  virtual void OnFirstFrameRender() = 0;
 };
 
 }  // namespace media