WebSQL: Add missing getExecutionContext() null check

WebSQL: Add missing getExecutionContext() null check

Following r419951 getExecutionContext() may return null, so
return value must be checked.

BUG=653272
R=haraken@chromium.org

Committed: https://crrev.com/6584c5e9bdbc3af9f7995a25252d5b4ef802e7c9
Cr-Commit-Position: refs/heads/master@{#423764}

[jsbell, 2016-10-06 23:18:33]

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

[commit-bot: I haz the power, 2016-10-06 23:19:13]

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

[jsbell, 2016-10-06 23:22:03]

haraken@ - r? cq?

Note that this repro is synchronous and really simple - just need script in an
iframe that does:

let o = createSomeDOMObject();
frameElement.remove();
o.doAnythingThatUsesExecutionContext();

So I expect we're going to find more of these.

[jsbell, 2016-10-06 23:23:44]

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

[commit-bot: I haz the power, 2016-10-06 23:24:16]

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

[haraken, 2016-10-06 23:29:04]

Thanks, LGTM!

[haraken, 2016-10-06 23:29:09]

The CQ bit was unchecked by haraken@chromium.org

[haraken, 2016-10-06 23:29:14]

The CQ bit was checked by haraken@chromium.org

[commit-bot: I haz the power, 2016-10-06 23:29:36]

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, 2016-10-07 00:42:54]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-10-07 00:46:07]

Description was changed from

==========
WebSQL: Add missing getExecutionContext() null check

Following r419951 getExecutionContext() may return null, so
return value must be checked.

BUG=653272
R=haraken@chromium.org
==========

to

==========
WebSQL: Add missing getExecutionContext() null check

Following r419951 getExecutionContext() may return null, so
return value must be checked.

BUG=653272
R=haraken@chromium.org

Committed: https://crrev.com/6584c5e9bdbc3af9f7995a25252d5b4ef802e7c9
Cr-Commit-Position: refs/heads/master@{#423764}
==========

[commit-bot: I haz the power, 2016-10-07 00:46:07]

Patchset 2 (id:??) landed as
https://crrev.com/6584c5e9bdbc3af9f7995a25252d5b4ef802e7c9
Cr-Commit-Position: refs/heads/master@{#423764}