cc: Handle GrContext::wrapBackendTexture failures properly.

cc: Handle GrContext::wrapBackendTexture failures properly.

GrContext::wrapBackendTexture will return null in case of failure
but the compositor assumes that this will never happen. This will
make GetSkSurface early out if the return value of
GrContext::wrapBackendTexture is null.

BUG=419136
Committed: https://crrev.com/00f53a49a90a56c22d412a8e0e27e3a4a6ae5155
Cr-Commit-Position: refs/heads/master@{#302477}

[reveman, 2014-11-03 19:09:28]

reveman@chromium.org changed reviewers:
+ alokp@chromium.org, piman@chromium.org

[piman, 2014-11-03 19:13:11]

lgtm

[reveman, 2014-11-03 19:15:04]

The CQ bit was checked by reveman@chromium.org

[commit-bot: I haz the power, 2014-11-03 19:17:23]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/696353003/1

[commit-bot: I haz the power, 2014-11-03 20:57:01]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2014-11-03 20:57:30]

Patchset 1 (id:??) landed as
https://crrev.com/00f53a49a90a56c22d412a8e0e27e3a4a6ae5155
Cr-Commit-Position: refs/heads/master@{#302477}