Improve robustness of lost context checks in Canvas2DLayerBridge

Improve robustness of lost context checks in Canvas2DLayerBridge

To avoid crashes caused by unexpected inconsistent states when a GPU
context loss occurs, we make Canvas2DLayerBridge::contextGL return
null when the checkSurfaceValid fails in order to allow calling code
to abort cleanly by performing null checks on the return of contextGL.

BUG=598712
Committed: https://crrev.com/5d0d1d13c683a3a8b9a200332e9d479d5d14d4f1
Cr-Commit-Position: refs/heads/master@{#391096}

[Justin Novosad, 2016-05-02 15:19:59]

junov@chromium.org changed reviewers:
+ senorblanco@chromium.org

[Justin Novosad, 2016-05-02 15:20:00]

PTAL

[Stephen White, 2016-05-02 17:28:51]

LGTM

[Justin Novosad, 2016-05-02 17:51:57]

The CQ bit was checked by junov@chromium.org

[commit-bot: I haz the power, 2016-05-02 17:52:21]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1934363002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1934363002/1

[commit-bot: I haz the power, 2016-05-02 21:33:45]

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

[commit-bot: I haz the power, 2016-05-02 21:33:46]

Try jobs failed on following builders:
  win_chromium_rel_ng on tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_rel_...)

[Justin Novosad, 2016-05-02 22:15:28]

The CQ bit was checked by junov@chromium.org

[commit-bot: I haz the power, 2016-05-02 22:15:57]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1934363002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1934363002/1

[Justin Novosad, 2016-05-02 22:18:09]

Description was changed from

==========
Improve robustness of lost context checks in Canvas2DLayerBridge

To avoid crashes cause by unexpected incoinsistent state when a GPU
context loss occurs, we make Canvas2DLayerBridge::contextGL return
null when the checkSurfaceValid fails in order to allow calling code
to abort cleanly by performing null checks on the return of contextGL.

BUG=598712
==========

to

==========
Improve robustness of lost context checks in Canvas2DLayerBridge

To avoid crashes caused by unexpected inconsistent states when a GPU
context loss occurs, we make Canvas2DLayerBridge::contextGL return
null when the checkSurfaceValid fails in order to allow calling code
to abort cleanly by performing null checks on the return of contextGL.

BUG=598712
==========

[commit-bot: I haz the power, 2016-05-02 23:35:53]

Description was changed from

==========
Improve robustness of lost context checks in Canvas2DLayerBridge

To avoid crashes caused by unexpected inconsistent states when a GPU
context loss occurs, we make Canvas2DLayerBridge::contextGL return
null when the checkSurfaceValid fails in order to allow calling code
to abort cleanly by performing null checks on the return of contextGL.

BUG=598712
==========

to

==========
Improve robustness of lost context checks in Canvas2DLayerBridge

To avoid crashes caused by unexpected inconsistent states when a GPU
context loss occurs, we make Canvas2DLayerBridge::contextGL return
null when the checkSurfaceValid fails in order to allow calling code
to abort cleanly by performing null checks on the return of contextGL.

BUG=598712
==========

[commit-bot: I haz the power, 2016-05-02 23:35:55]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-05-02 23:38:37]

Description was changed from

==========
Improve robustness of lost context checks in Canvas2DLayerBridge

To avoid crashes caused by unexpected inconsistent states when a GPU
context loss occurs, we make Canvas2DLayerBridge::contextGL return
null when the checkSurfaceValid fails in order to allow calling code
to abort cleanly by performing null checks on the return of contextGL.

BUG=598712
==========

to

==========
Improve robustness of lost context checks in Canvas2DLayerBridge

To avoid crashes caused by unexpected inconsistent states when a GPU
context loss occurs, we make Canvas2DLayerBridge::contextGL return
null when the checkSurfaceValid fails in order to allow calling code
to abort cleanly by performing null checks on the return of contextGL.

BUG=598712

Committed: https://crrev.com/5d0d1d13c683a3a8b9a200332e9d479d5d14d4f1
Cr-Commit-Position: refs/heads/master@{#391096}
==========

[commit-bot: I haz the power, 2016-05-02 23:38:38]

Patchset 1 (id:??) landed as
https://crrev.com/5d0d1d13c683a3a8b9a200332e9d479d5d14d4f1
Cr-Commit-Position: refs/heads/master@{#391096}