Fix remote frame origin access in ContentWatcher::NotifyBrowserOfChange.

Fix remote frame origin access in ContentWatcher::NotifyBrowserOfChange.

The frame traversal in that function was accessing the frame's
SecurityOrigin via the document(), which is incorrect in the case of
remote frames which have no document().

BUG=581274
Committed: https://crrev.com/1cf50512acf1e7098750465e4cb94a27d614c480
Cr-Commit-Position: refs/heads/master@{#371592}

[alexmos, 2016-01-26 18:27:50]

alexmos@chromium.org changed reviewers:
+ rdevlin.cronin@chromium.org

[alexmos, 2016-01-26 18:27:50]

Devlin, please take a look.  This is just an easy fix for a crash we hit in our
isolate-extensions trial.  

I also went through the other uses of "document().securityOrigin()" to see if we
have this problem anywhere else, and the remaining call sites all seem to be
doing this on local frames, which is safe.

[Devlin, 2016-01-26 19:00:52]

lgtm

[alexmos, 2016-01-26 19:51:43]

The CQ bit was checked by alexmos@chromium.org

[commit-bot: I haz the power, 2016-01-26 19:53:24]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1634203002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1634203002/1

[commit-bot: I haz the power, 2016-01-26 20:48:12]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-01-26 20:49:34]

Description was changed from

==========
Fix remote frame origin access in ContentWatcher::NotifyBrowserOfChange.

The frame traversal in that function was accessing the frame's
SecurityOrigin via the document(), which is incorrect in the case of
remote frames which have no document().

BUG=581274
==========

to

==========
Fix remote frame origin access in ContentWatcher::NotifyBrowserOfChange.

The frame traversal in that function was accessing the frame's
SecurityOrigin via the document(), which is incorrect in the case of
remote frames which have no document().

BUG=581274

Committed: https://crrev.com/1cf50512acf1e7098750465e4cb94a27d614c480
Cr-Commit-Position: refs/heads/master@{#371592}
==========

[commit-bot: I haz the power, 2016-01-26 20:49:38]

Patchset 1 (id:??) landed as
https://crrev.com/1cf50512acf1e7098750465e4cb94a27d614c480
Cr-Commit-Position: refs/heads/master@{#371592}