Fix an issue that a browser seek is requested after decoder draining is interrupted.

Fix an issue that a browser seek is requested after decoder draining is interrupted.

When decoder is draining, the current access unit is pointing to the config change AU.
If something interrupts the draining, a surface change for example,
CreateMediaCodecBridge() will fail because the current AU is not an i-frame.
This will cause an unnecessary browser seek.
To avoid this, we should call OnDecoderDrained() first to let video decoder know that config change AU is consumed.

The issue is captured by the DecoderDrainInterruptedBySurfaceChange test on nexus 9.
And this change reenables that test, so no additional test is added.

BUG=429889
Committed: https://crrev.com/800e030e283ccc0301b8d980e0ae152b93cb3420
Cr-Commit-Position: refs/heads/master@{#302640}

[qinmin, 2014-11-04 00:13:24]

qinmin@chromium.org changed reviewers:
+ wolenetz@chromium.org

[qinmin, 2014-11-04 00:13:24]

PTAL

[wolenetz, 2014-11-04 18:19:26]

lgtm

[qinmin, 2014-11-04 18:38:14]

The CQ bit was checked by qinmin@chromium.org

[commit-bot: I haz the power, 2014-11-04 18:39:34]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/699763002/1

[commit-bot: I haz the power, 2014-11-04 19:30:12]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2014-11-04 19:30:56]

Patchset 1 (id:??) landed as
https://crrev.com/800e030e283ccc0301b8d980e0ae152b93cb3420
Cr-Commit-Position: refs/heads/master@{#302640}