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

media/base/renderer_client.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MEDIA_BASE_RENDERER_CLIENT_H_
 #define MEDIA_BASE_RENDERER_CLIENT_H_
 
 #include "base/time/time.h"
 #include "media/base/pipeline_status.h"
 #include "ui/gfx/geometry/size.h"
@@ skipping 23 matching lines @@
   // Only used if media stream contains video track.
   virtual void OnVideoNaturalSizeChange(const gfx::Size& size) = 0;
 
   // Executed for the first video frame and whenever opacity changes.
   // Only used if media stream contains video track.
   virtual void OnVideoOpacityChange(bool opaque) = 0;
 
   // 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
 
 #endif  // MEDIA_BASE_RENDERER_CLIENT_H_