Ensure media's buffered ranges always have a range that includes currentTime.

media/filters/ffmpeg_demuxer.h

Index: media/filters/ffmpeg_demuxer.h
diff --git a/media/filters/ffmpeg_demuxer.h b/media/filters/ffmpeg_demuxer.h
index dee6db350313d830f67e5a02e5f0144952e67c2a..3a9acbf8a8b0ed56d6ff7d5acf6fb86d0a5a03d5 100644
--- a/media/filters/ffmpeg_demuxer.h
+++ b/media/filters/ffmpeg_demuxer.h
@@ -47,11 +47,14 @@ class BitstreamConverter;
 class FFmpegDemuxer;
 class ScopedPtrAVFreePacket;
 
+typedef base::Callback<void(base::TimeDelta, base::TimeDelta)> NotifyBufferedCB;
+
 class FFmpegDemuxerStream : public DemuxerStream {
  public:
   // Keeps a copy of |demuxer| and initializes itself using information
   // inside |stream|.  Both parameters must outlive |this|.
-  FFmpegDemuxerStream(FFmpegDemuxer* demuxer, AVStream* stream);
+  FFmpegDemuxerStream(const NotifyBufferedCB& notify_buffered_cb_,
+                      FFmpegDemuxer* demuxer, AVStream* stream);
 
   // Returns true is this stream has pending reads, false otherwise.
   //
@@ -107,6 +110,7 @@ class FFmpegDemuxerStream : public DemuxerStream {
   static base::TimeDelta ConvertStreamTimestamp(const AVRational& time_base,
                                                 int64 timestamp);
 
+  NotifyBufferedCB notify_buffered_cb_;
   FFmpegDemuxer* demuxer_;
   AVStream* stream_;
   AudioDecoderConfig audio_config_;
@@ -115,6 +119,7 @@ class FFmpegDemuxerStream : public DemuxerStream {
   base::TimeDelta duration_;
   bool discontinuous_;
   bool stopped_;
+  base::TimeDelta last_packet_timestamp_;
 
   typedef std::deque<scoped_refptr<DecoderBuffer> > BufferQueue;
   BufferQueue buffer_queue_;
@@ -205,6 +210,11 @@ class MEDIA_EXPORT FFmpegDemuxer : public Demuxer, public FFmpegURLProtocol {
   // read or kReadError in case of error.
   virtual void SignalReadCompleted(int size);
 
+  // Callback for DemuxerStreams to notify us they've buffered a time range,
+  // which we then percolate upwards.
+  void NotifyBufferedRange(
+      int stream_id, base::TimeDelta start, base::TimeDelta end);
+
   DemuxerHost* host_;
 
   MessageLoop* message_loop_;
@@ -224,6 +234,9 @@ class MEDIA_EXPORT FFmpegDemuxer : public Demuxer, public FFmpegURLProtocol {
   typedef std::vector<scoped_refptr<FFmpegDemuxerStream> > StreamVector;
   StreamVector streams_;
 
+  // The times buffered by each stream.
+  std::vector<Ranges<base::TimeDelta> > buffered_times_;
+
   // Reference to the data source. Asynchronous read requests are submitted to
   // this object.
   scoped_refptr<DataSource> data_source_;