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 2dd263462b1589711786111bfed6afd8f99cc495..46149f1be09da647e05408c403cc8999e1a1e6b5 100644
--- a/media/filters/video_renderer_base.h
+++ b/media/filters/video_renderer_base.h
@@ -54,7 +54,8 @@ class MEDIA_EXPORT VideoRendererBase
   // VideoRenderer implementation.
   virtual void Initialize(VideoDecoder* decoder,
                           const PipelineStatusCB& callback,
-                          const StatisticsCallback& stats_callback) OVERRIDE;
+                          const StatisticsCallback& stats_callback,
+                          const VideoTimeCB& video_time_cb) OVERRIDE;
   virtual bool HasEnded() OVERRIDE;
 
   // PlatformThread::Delegate implementation.
@@ -184,6 +185,7 @@ class MEDIA_EXPORT VideoRendererBase
   base::Closure flush_callback_;
   FilterStatusCB seek_cb_;
   StatisticsCallback statistics_callback_;
+  VideoTimeCB video_time_cb_;
 
   base::TimeDelta seek_timestamp_;