[M55] Use FFmpeg default padding when allocating audio buffers.

[M55] Use FFmpeg default padding when allocating audio buffers.

Previously, we would pad to the alignment size when allocating an
audio buffer.  However, this did not always provide enough padding
to avoid overruns.

Instead, we now let FFmpeg determine the correct padding for us.

BUG=658440
Review-Url: https://codereview.chromium.org/2464963003
Cr-Commit-Position: refs/heads/master@{#429014}
(cherry picked from commit b8733772baf52a693ab6a887373feaa6b91c7cdd)

Committed: https://chromium.googlesource.com/chromium/src/+/6a4696cdc766320ab841bb1ad4ef7c4665e6431e

[liberato (no reviews please), 2016-11-07 19:55:59]

Description was changed from

==========
[M55] Use FFmpeg default padding when allocating audio buffers.

Previously, we would pad to the alignment size when allocating an
audio buffer.  However, this did not always provide enough padding
to avoid overruns.

Instead, we now let FFmpeg determine the correct padding for us.

BUG=658440

Review-Url: https://codereview.chromium.org/2464963003
Cr-Commit-Position: refs/heads/master@{#429014}
(cherry picked from commit b8733772baf52a693ab6a887373feaa6b91c7cdd)
==========

to

==========
[M55] Use FFmpeg default padding when allocating audio buffers.

Previously, we would pad to the alignment size when allocating an
audio buffer.  However, this did not always provide enough padding
to avoid overruns.

Instead, we now let FFmpeg determine the correct padding for us.

BUG=658440

Review-Url: https://codereview.chromium.org/2464963003
Cr-Commit-Position: refs/heads/master@{#429014}
(cherry picked from commit b8733772baf52a693ab6a887373feaa6b91c7cdd)

Committed:
https://chromium.googlesource.com/chromium/src/+/6a4696cdc766320ab841bb1ad4ef...
==========

[liberato (no reviews please), 2016-11-07 19:56:00]

Committed patchset #1 (id:1) manually as
6a4696cdc766320ab841bb1ad4ef7c4665e6431e.