Add gapless playback support for AAC playback.

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 26d09b1e5c6257f9dc6aaf33e364af27c7665cb5..a852031dc6a80a442c5862c17497835053505224 100644
--- a/media/filters/chunk_demuxer.cc
+++ b/media/filters/chunk_demuxer.cc
@@ -567,6 +567,8 @@ bool SourceState::OnNewConfigs(
         DVLOG(1) << "Failed to add audio track to frame processor.";
         return false;
       }
+    } else {
+      frame_processor_->clear_audio_preroll_buffer();

[wolenetz, 2014/05/23 19:59:45]

I would like to see a test that preroll is cleared if config change occurs prior
to next buffer even if next buffer abuts the preroll buffer.

[DaleCurtis, 2014/05/23 21:46:26]

I'll address this in the next patch set. It's proving really tricky to write a
test to do this and I want to get this up for review before acolwell@ heads out
on vacation.

[DaleCurtis, 2014/05/24 00:43:33]

Done, but the test fails using the new frame processor, per our offline
discussion, since it fails buffers with negative timestamps even if they would
be discarded by the append window.

     }
 
     success &= audio_->UpdateAudioConfig(audio_config, log_cb_);