Merge M52: "Fix dropped demuxer buffers for fallback decoder"

Merge M52: "Fix dropped demuxer buffers for fallback decoder"

An edge case was missed due to a typo in a DCHECK, during the original
fallback decoder submission.

Currently, the following scenario can happen:
- DecoderStream requests buffers from the demuxer
  (STATE_PENDING_DEMUXER_READ).
- |decoder_| returns a DECODE_ERROR before a frame was ouptutted,
  initiating a decoder fallback (STATE_REINITIALIZING_DECODER).
- OnDecoderSelected() successfully completes (STATE_NORMAL).
- OnBufferReady() is called back (the typo in the DCHECK meant we never
  considered when we enter the function in STATE_NORMAL). We return at
  line 601 because the state is not STATE_PENDING_DEMUXER_READ, and drop
  the buffer.

This CL fixes the typo, and changes so we only drop the buffer whilst in
STATE_ERROR, and also handles the case where we had saved buffers in the
fallback buffer queue.

BUG=597605, 615141
TEST= Setup GpuVideoDecoder to fail 10% and refreshed the page for
several minutes. Hard to test the end to end though...

Review-Url: https://codereview.chromium.org/2012293002
Cr-Commit-Position: refs/heads/master@{#396371}
(cherry picked from commit 4849043c3e003ef57a431552f9a97cf159debd06)

Committed: https://chromium.googlesource.com/chromium/src/+/62136bd4d4f641a0f516badd93c200eaf2bca285

[DaleCurtis, 2016-06-30 01:39:05]

Description was changed from

==========
Merge M52: "Fix dropped demuxer buffers for fallback decoder"

An edge case was missed due to a typo in a DCHECK, during the original
fallback decoder submission.

Currently, the following scenario can happen:
- DecoderStream requests buffers from the demuxer
  (STATE_PENDING_DEMUXER_READ).
- |decoder_| returns a DECODE_ERROR before a frame was ouptutted,
  initiating a decoder fallback (STATE_REINITIALIZING_DECODER).
- OnDecoderSelected() successfully completes (STATE_NORMAL).
- OnBufferReady() is called back (the typo in the DCHECK meant we never
  considered when we enter the function in STATE_NORMAL). We return at
  line 601 because the state is not STATE_PENDING_DEMUXER_READ, and drop
  the buffer.

This CL fixes the typo, and changes so we only drop the buffer whilst in
STATE_ERROR, and also handles the case where we had saved buffers in the
fallback buffer queue.

BUG=597605, 615141
TEST= Setup GpuVideoDecoder to fail 10% and refreshed the page for
several minutes. Hard to test the end to end though...

Review-Url: https://codereview.chromium.org/2012293002
Cr-Commit-Position: refs/heads/master@{#396371}
(cherry picked from commit 4849043c3e003ef57a431552f9a97cf159debd06)
==========

to

==========
Merge M52: "Fix dropped demuxer buffers for fallback decoder"

An edge case was missed due to a typo in a DCHECK, during the original
fallback decoder submission.

Currently, the following scenario can happen:
- DecoderStream requests buffers from the demuxer
  (STATE_PENDING_DEMUXER_READ).
- |decoder_| returns a DECODE_ERROR before a frame was ouptutted,
  initiating a decoder fallback (STATE_REINITIALIZING_DECODER).
- OnDecoderSelected() successfully completes (STATE_NORMAL).
- OnBufferReady() is called back (the typo in the DCHECK meant we never
  considered when we enter the function in STATE_NORMAL). We return at
  line 601 because the state is not STATE_PENDING_DEMUXER_READ, and drop
  the buffer.

This CL fixes the typo, and changes so we only drop the buffer whilst in
STATE_ERROR, and also handles the case where we had saved buffers in the
fallback buffer queue.

BUG=597605, 615141
TEST= Setup GpuVideoDecoder to fail 10% and refreshed the page for
several minutes. Hard to test the end to end though...

Review-Url: https://codereview.chromium.org/2012293002
Cr-Commit-Position: refs/heads/master@{#396371}
(cherry picked from commit 4849043c3e003ef57a431552f9a97cf159debd06)

Committed:
https://chromium.googlesource.com/chromium/src/+/62136bd4d4f641a0f516badd93c2...
==========

[DaleCurtis, 2016-06-30 01:39:07]

Committed patchset #1 (id:1) manually as
62136bd4d4f641a0f516badd93c200eaf2bca285.