Fix media timeline so that thumb never exceeds buffered data

media/filters/video_renderer_base.h

Index: media/filters/video_renderer_base.h
diff --git a/media/filters/video_renderer_base.h b/media/filters/video_renderer_base.h
index d6dad420c3daf987b7a52d52a6e4fb31f5d71b8e..c9916916dba01126eef6c09e24b260b27cf25f6c 100644
--- a/media/filters/video_renderer_base.h
+++ b/media/filters/video_renderer_base.h
@@ -53,8 +53,9 @@ class MEDIA_EXPORT VideoRendererBase
 
   // VideoRenderer implementation.
   virtual void Initialize(VideoDecoder* decoder,
-                          const base::Closure& callback,
-                          const StatisticsCallback& stats_callback) OVERRIDE;
+                          const base::Closure& init_cb,
+                          const StatisticsCallback& stats_callback,
+                          const VideoTimeCB& video_time_cb) OVERRIDE;
   virtual bool HasEnded() OVERRIDE;
 
   // PlatformThread::Delegate implementation.
@@ -181,6 +182,7 @@ class MEDIA_EXPORT VideoRendererBase
   base::Closure flush_callback_;
   FilterStatusCB seek_cb_;
   StatisticsCallback statistics_callback_;
+  VideoTimeCB video_time_cb_;
 
   base::TimeDelta seek_timestamp_;