Support setting an explicit duration on MediaSource objects

media/filters/chunk_demuxer.cc

Index: media/filters/chunk_demuxer.cc
diff --git a/media/filters/chunk_demuxer.cc b/media/filters/chunk_demuxer.cc
index 6322f5a97b99e91e8797eff90a6403869019bcb1..981595a0da4253e8c51ea451f278e96cf26ae99e 100644
--- a/media/filters/chunk_demuxer.cc
+++ b/media/filters/chunk_demuxer.cc
@@ -181,6 +181,9 @@ class ChunkDemuxerStream : public DemuxerStream {
   // Returns true if buffers were successfully added.
   bool Append(const StreamParser::BufferQueue& buffers);
 
+  // Signal to the stream that duration has changed to |duration|.
+  void OnSetDuration(base::TimeDelta duration);
+
   // Returns the range of buffered data in this stream, capped at |duration|.
   Ranges<TimeDelta> GetBufferedRanges(base::TimeDelta duration) const;
 
@@ -335,6 +338,11 @@ bool ChunkDemuxerStream::Append(const StreamParser::BufferQueue& buffers) {
   return true;
 }
 
+void ChunkDemuxerStream::OnSetDuration(base::TimeDelta duration) {
+  base::AutoLock auto_lock(lock_);
+  stream_->OnSetDuration(duration);
+}
+
 Ranges<TimeDelta> ChunkDemuxerStream::GetBufferedRanges(
     base::TimeDelta duration) const {
   base::AutoLock auto_lock(lock_);
@@ -824,6 +832,18 @@ void ChunkDemuxer::Abort(const std::string& id) {
   stream_parser_map_[id]->Flush();
 }
 
+void ChunkDemuxer::SetDuration(base::TimeDelta duration) {
+  DVLOG(1) << "SetDuration(" << duration.InSecondsF() << ")";
+
+  UpdateDuration(duration);

[acolwell GONE FROM CHROMIUM, 2012/08/24 18:19:10]

I think you need a 
if(duration != duration_)
  return;

otherwise I believe 'mediaSource.duration = mediaSource.duration;' in JavaScript
will DCHECK.

[vrk (LEFT CHROMIUM), 2012/08/28 00:03:22]

Did == instead :)

+
+  if (audio_)
+    audio_->OnSetDuration(duration);
+
+  if (video_)
+    video_->OnSetDuration(duration);
+}
+
 bool ChunkDemuxer::SetTimestampOffset(const std::string& id, TimeDelta offset) {
   DVLOG(1) << "SetTimestampOffset(" << id << ", " << offset.InSecondsF() << ")";
   CHECK(IsValidId(id));