MSE: Log more details during completing ChunkDemuxerStream reads

MSE: Log more details during completing ChunkDemuxerStream reads

This change adds more debug logging to help diagnose issues occurring
during completing pending reads of ChunkDemuxerStream. It also includes
more logs in SourceBufferStream::GetNextBuffer().
These logs are useful for debugging issues like the referenced bug.

R=dalecurtis@chromium.org
BUG=423858
Committed: https://crrev.com/ecf63c8e50754572ed642ac5a1e7789afef4e83c
Cr-Commit-Position: refs/heads/master@{#307104}

[wolenetz, 2014-12-05 00:28:33]

Please take a look.

Thanks,
Matt

[DaleCurtis, 2014-12-05 00:33:41]

lgtm

[wolenetz, 2014-12-05 00:36:54]

The CQ bit was checked by wolenetz@chromium.org

[commit-bot: I haz the power, 2014-12-05 00:38:09]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/761963006/1

[commit-bot: I haz the power, 2014-12-05 01:46:17]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-12-05 01:46:17]

Try jobs failed on following builders:
  linux_chromium_asan_rel on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)
  linux_chromium_rel_ng on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[wolenetz, 2014-12-05 22:13:43]

Dale - PTAL @ PS2. PS1 broke things...

https://codereview.chromium.org/761963006/diff/1/media/filters/source_buffer_...
File media/filters/source_buffer_stream.cc (right):

https://codereview.chromium.org/761963006/diff/1/media/filters/source_buffer_...
media/filters/source_buffer_stream.cc:967: << ": no previously pending buffer,
returning status " << status;
Updated the message for clarity. Still a little grey, but better.

https://codereview.chromium.org/761963006/diff/1/media/filters/source_buffer_...
media/filters/source_buffer_stream.cc:983:
DCHECK(pending_buffer_->preroll_buffer().get());
Oops - this DCHECK must be done *before*
HandleNextBufferWithPreroll(out_buffer).

[DaleCurtis, 2014-12-05 22:14:54]

Ah yeah, sorry I didn't notice you reordered that :|

lgtm

[wolenetz, 2014-12-05 22:17:19]

Thanks - All was well until preroll/splicing occurred, which of course didn't
get hit when I was investigating bug 423858 using PS1 :/

[wolenetz, 2014-12-05 22:17:30]

The CQ bit was checked by wolenetz@chromium.org

[commit-bot: I haz the power, 2014-12-05 22:18:08]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/761963006/20001

[commit-bot: I haz the power, 2014-12-05 23:22:31]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2014-12-05 23:23:15]

Patchset 2 (id:??) landed as
https://crrev.com/ecf63c8e50754572ed642ac5a1e7789afef4e83c
Cr-Commit-Position: refs/heads/master@{#307104}