Fix media_log() crash in fuzzer tests.

Fix media_log() crash in fuzzer tests.

When called from this context, no MediaLog exists, so ensure we
don't try to use it.

BUG=610848, 650735, 651739
TEST=libfuzzer

Committed: https://crrev.com/c27e432072ef22112251bbe874c8a1060a0c7ca5
Cr-Commit-Position: refs/heads/master@{#422182}

[DaleCurtis, 2016-09-30 17:56:30]

Description was changed from

==========
Fix media_log() crash in fuzzer tests.

When called from this context, no MediaLog exists, so ensure we
don't try to use it.

BUG=651739
TEST=libfuzzer
==========

to

==========
Fix media_log() crash in fuzzer tests.

When called from this context, no MediaLog exists, so ensure we
don't try to use it.

BUG=610848, 650735, 651739
TEST=libfuzzer
==========

[DaleCurtis, 2016-09-30 17:56:30]

dalecurtis@chromium.org changed reviewers:
+ sandersd@chromium.org

[sandersd (OOO until July 31), 2016-09-30 18:00:13]

lgtm

Would it not be better to pass in a null log sink?

[DaleCurtis, 2016-09-30 18:04:54]

The CQ bit was checked by dalecurtis@chromium.org

[DaleCurtis, 2016-09-30 18:04:55]

Would, but not all callers have a MediaLog and for those that do... code is now
used in areas which are not StreamParsers, MediaLog is supplied by Initialize()
which takes ~7 other callbacks.

This code can probably be teased apart better, but will require some larger
refactorings.

[commit-bot: I haz the power, 2016-09-30 18:05:31]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-09-30 19:34:58]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-09-30 19:37:04]

Description was changed from

==========
Fix media_log() crash in fuzzer tests.

When called from this context, no MediaLog exists, so ensure we
don't try to use it.

BUG=610848, 650735, 651739
TEST=libfuzzer
==========

to

==========
Fix media_log() crash in fuzzer tests.

When called from this context, no MediaLog exists, so ensure we
don't try to use it.

BUG=610848, 650735, 651739
TEST=libfuzzer

Committed: https://crrev.com/c27e432072ef22112251bbe874c8a1060a0c7ca5
Cr-Commit-Position: refs/heads/master@{#422182}
==========

[commit-bot: I haz the power, 2016-09-30 19:37:06]

Patchset 1 (id:??) landed as
https://crrev.com/c27e432072ef22112251bbe874c8a1060a0c7ca5
Cr-Commit-Position: refs/heads/master@{#422182}