Set WebMediaPlayer as an opaque layer

Set WebMediaPlayer as an opaque layer

This CL changes WebMediaPlayer to an opaque layer due to 
performance regressions caused by transparency.

BUG=647886

[emircan, 2016-09-16 16:39:27]

The CQ bit was checked by emircan@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-09-16 16:39:43]

Dry run: 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, 2016-09-16 17:18:42]

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

[commit-bot: I haz the power, 2016-09-16 17:18:44]

Dry run: This issue passed the CQ dry run.

[emircan, 2016-09-17 00:28:01]

Description was changed from

==========
revert opaqueness

BUG=
==========

to

==========
Set WebMediaPlayer as an opaque layer

This CL changes WebMediaPlayer to an opaque layer due to 
performance regressions caused by transparency.

BUG=647886
==========

[emircan, 2016-09-17 01:02:22]

emircan@chromium.org changed reviewers:
+ mcasas@chromium.org

[emircan, 2016-09-17 01:02:22]

PTAL.

[emircan, 2016-09-17 01:05:16]

emircan@chromium.org changed reviewers:
+ tommi@chromium.org

[mcasas, 2016-09-17 03:29:37]

On 2016/09/17 01:02:22, emircan wrote:
> PTAL.

lgtm

[emircan, 2016-09-21 17:22:27]

Closing this in favor of https://codereview.chromium.org/2348903003/. Thanks for
your time.