mojo: Add proper implementation of DetachFromClient to OutputSurfaceMojo.

mojo: Add proper implementation of DetachFromClient to OutputSurfaceMojo.

BUG=523411, 525811
TBR=sky@chromium.org
TEST=mojo_runner --use-temporary-user-data-dir --enable-html-viewer-test-interface --use-x11-test-config --override-use-gl-with-osmesa-for-tests --gtest_filter=AXProviderTest.HelloWorld mojo:html_viewer_apptests
NOTRY=true

Committed: https://crrev.com/18167629b4bdc20e951b71e9c546ed0c1030090f
Cr-Commit-Position: refs/heads/master@{#350483}

[reveman, 2015-09-24 04:58:42]

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

[reveman, 2015-09-24 05:00:15]

I think we can land this without going through the try bots. Verified that it
fixes the issue by building and running this locally.

[msw, 2015-09-24 05:02:37]

lgtm, thanks!

[reveman, 2015-09-24 05:03:08]

The CQ bit was checked by reveman@chromium.org

[commit-bot: I haz the power, 2015-09-24 05:03:34]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1362243002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1362243002/1

[commit-bot: I haz the power, 2015-09-24 05:10:10]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-09-24 05:10:52]

Patchset 1 (id:??) landed as
https://crrev.com/18167629b4bdc20e951b71e9c546ed0c1030090f
Cr-Commit-Position: refs/heads/master@{#350483}