Remove CHECK from createChildFrame

Remove CHECK from createChildFrame

The CHECK helped narrow down the reasons for the failure and we know now
that the sync IPC is failing. It needs more investigation why it happens,
but the check can be removed now.

BUG=397744
Committed: https://crrev.com/000da13e51951ee9878eeb195e7f2d5cd43d2bb7
Cr-Commit-Position: refs/heads/master@{#316325}

[Charlie Reis, 2015-02-13 22:21:00]

creis@chromium.org changed reviewers:
+ creis@chromium.org

[Charlie Reis, 2015-02-13 22:21:00]

LGTM

[nasko, 2015-02-13 22:21:21]

The CQ bit was checked by nasko@chromium.org

[commit-bot: I haz the power, 2015-02-13 22:21:53]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/922373004/1

[commit-bot: I haz the power, 2015-02-13 23:34:07]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-02-13 23:35:18]

Patchset 1 (id:??) landed as
https://crrev.com/000da13e51951ee9878eeb195e7f2d5cd43d2bb7
Cr-Commit-Position: refs/heads/master@{#316325}