Enhance WebMediaPlayer::buffered() to account for evicted ranges.

media/blink/buffered_data_source.h

Index: media/blink/buffered_data_source.h
diff --git a/media/blink/buffered_data_source.h b/media/blink/buffered_data_source.h
index 5ae7d935c622931f27fff2682aadb30f8e182565..f0dbcc298ff29fb4ef93fe0fb0871aa311cb7be3 100644
--- a/media/blink/buffered_data_source.h
+++ b/media/blink/buffered_data_source.h
@@ -29,10 +29,11 @@ class MEDIA_EXPORT BufferedDataSourceHost {
   virtual void SetTotalBytes(int64 total_bytes) = 0;
 
   // Notify the host that byte range [start,end] has been buffered.
-  // TODO(fischman): remove this method when demuxing is push-based instead of
-  // pull-based.  http://crbug.com/131444

[scherkus (not reviewing), 2014/09/17 16:25:28]

while http://crbug.com/131444 has been closed as WontFix the general idea still
lives on -- BufferedDataSourceHost should really go away and we should move to
purely time-based demuxing

I'm having trouble finding the relevant bug though :\

   virtual void AddBufferedByteRange(int64 start, int64 end) = 0;
 
+  // Notify the host that byte range [0, end) has been evicted.
+  virtual void RemoveBufferedByteRange(int64 end) = 0;
+
  protected:
   virtual ~BufferedDataSourceHost() {};
 };
@@ -152,7 +153,7 @@ class MEDIA_EXPORT BufferedDataSource : public DataSource {
   // BufferedResourceLoader callbacks.
   void ReadCallback(BufferedResourceLoader::Status status, int bytes_read);
   void LoadingStateChangedCallback(BufferedResourceLoader::LoadingState state);
-  void ProgressCallback(int64 position);
+  void ProgressCallback(int64 earliest_position, int64 position);
 
   // Update |loader_|'s deferring strategy in response to a play/pause, or
   // change in playback rate.