Update extensions::MessagingBindings to use WebScopedWindowFocusAllowedIndicator with WebDocument.

Update extensions::MessagingBindings to use WebScopedWindowFocusAllowedIndicator with WebDocument.

This will allow Blink to delete some deprecated code.

This is part of a three-sided CL:
Part 1: https://codereview.chromium.org/777483004/
Part 2: <this>
Part 3: https://codereview.chromium.org/722423004

BUG=440740
Committed: https://crrev.com/ebb4bf8090b06979fd44411af69304b505681f4d
Cr-Commit-Position: refs/heads/master@{#307914}

Committed: https://crrev.com/9b4c024f001519ea0c35decc04335bb768190ad5
Cr-Commit-Position: refs/heads/master@{#326007}

[mlamouri (slow - plz ping), 2014-12-10 12:24:50]

mlamouri@chromium.org changed reviewers:
+ scheib@chromium.org

[mlamouri (slow - plz ping), 2014-12-10 12:33:33]

+CC mkwst@ and jochen@ given that they are reviewers for parts 1 and 3.

[scheib, 2014-12-10 20:39:47]

lgtm

[mlamouri (slow - plz ping), 2014-12-11 16:03:42]

The CQ bit was checked by mlamouri@chromium.org

[commit-bot: I haz the power, 2014-12-11 16:04:34]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/786403003/1

[commit-bot: I haz the power, 2014-12-11 16:55:37]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2014-12-11 16:56:25]

Patchset 1 (id:??) landed as
https://crrev.com/ebb4bf8090b06979fd44411af69304b505681f4d
Cr-Commit-Position: refs/heads/master@{#307914}

[Ken Rockot(use gerrit already), 2014-12-16 02:27:16]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/807593003/ by rockot@chromium.org.

The reason for reverting is: This CL or its dependency in blink
(https://codereview.chromium.org/803253003/) is the suspected source of issue
441968 (very prominent renderer crash), among other crashes. .

[scheib, 2015-03-24 21:47:31]

Closing out of date patch, reopen if appropriate.

[mlamouri (slow - plz ping), 2015-03-25 00:36:14]

On 2015/03/24 at 21:47:31, scheib wrote:
> Closing out of date patch, reopen if appropriate.

I still mean to try to land that. Low priority but I would prefer to keep it in
my radar.

[mlamouri (slow - plz ping), 2015-04-21 09:42:48]

The CQ bit was checked by mlamouri@chromium.org

[mlamouri (slow - plz ping), 2015-04-21 09:42:48]

The patchset sent to the CQ was uploaded after l-g-t-m from scheib@chromium.org
Link to the patchset: https://codereview.chromium.org/786403003/#ps20001 (title:
"rebase")

[commit-bot: I haz the power, 2015-04-21 09:43:00]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/786403003/20001

[commit-bot: I haz the power, 2015-04-21 10:44:03]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-04-21 10:44:59]

Patchset 2 (id:??) landed as
https://crrev.com/9b4c024f001519ea0c35decc04335bb768190ad5
Cr-Commit-Position: refs/heads/master@{#326007}