Fixed WebVR HTTP warning only rendering in the right eye

Fixed WebVR HTTP warning only rendering in the right eye

BUG=389343
Committed: https://crrev.com/038c81ab311795eacbb747f7b83e303040c24c5d
Cr-Commit-Position: refs/heads/master@{#432325}

[bajones, 2016-11-15 23:54:29]

bajones@chromium.org changed reviewers:
+ bshe@chromium.org, mthiesse@chromium.org

[bajones, 2016-11-15 23:54:29]

Issue was that we were clearing the canvas twice but disabling scissor testing
on the WebVR path, which made the second clear wipe out the first eye's content.

This new logic should be a little more efficient and less error prone. PTAL!

[mthiesse, 2016-11-16 00:11:56]

lgtm

[bajones, 2016-11-16 00:16:06]

The CQ bit was checked by bajones@chromium.org

[commit-bot: I haz the power, 2016-11-16 00:16:39]

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, 2016-11-16 00:47:38]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-11-16 00:51:58]

Description was changed from

==========
Fixed WebVR HTTP warning only rendering in the right eye

BUG=389343
==========

to

==========
Fixed WebVR HTTP warning only rendering in the right eye

BUG=389343

Committed: https://crrev.com/038c81ab311795eacbb747f7b83e303040c24c5d
Cr-Commit-Position: refs/heads/master@{#432325}
==========

[commit-bot: I haz the power, 2016-11-16 00:51:59]

Patchset 1 (id:??) landed as
https://crrev.com/038c81ab311795eacbb747f7b83e303040c24c5d
Cr-Commit-Position: refs/heads/master@{#432325}