Run queued tasks before shutting down after running a layout test.

Run queued tasks before shutting down after running a layout test.

Currently, when a layout test run finishes, the BlinkTestController
falls out of scope, which triggers shutdown of the RenderProcessHostImpl
used by the test. However, RenderProcessHostImpl posts a task to delete
itself, which is currently never run; this results in a
RenderProcessHostImpl outliving the UI MessageLoop and its
BrowserContext, inviting use-after-frees. This CL fixes this issue by
running queued tasks before shutting down the main runner.

BUG=610989
Committed: https://crrev.com/d8514447d66180f24e25713aea4445f80a9f4d6e
Cr-Commit-Position: refs/heads/master@{#393204}

[Sam McNally, 2016-05-12 00:24:47]

Description was changed from

==========
Run queued tasks before shutting down after running a layout test.

Currently, when a layout test run finishes, the BlinkTestController
falls out of scope, which triggers shutdown of the RenderProcessHostImpl
used by the test. However, RenderProcessHostImpl posts a task to delete
itself, which is currently never run; this results in a
RenderProcessHostImpl outliving the UI MessageLoop and its
BrowserContext, inviting in use-after-frees. This fixes this by running
queued tasks before shutting down the main runner.

BUG=610989
==========

to

==========
Run queued tasks before shutting down after running a layout test.

Currently, when a layout test run finishes, the BlinkTestController
falls out of scope, which triggers shutdown of the RenderProcessHostImpl
used by the test. However, RenderProcessHostImpl posts a task to delete
itself, which is currently never run; this results in a
RenderProcessHostImpl outliving the UI MessageLoop and its
BrowserContext, inviting use-after-frees. This CL fixes this issue by
running queued tasks before shutting down the main runner.

BUG=610989
==========

[Sam McNally, 2016-05-12 00:29:02]

sammc@chromium.org changed reviewers:
+ mkwst@chromium.org

[Mike West, 2016-05-12 05:39:41]

lgtm

[Sam McNally, 2016-05-12 06:29:11]

The CQ bit was checked by sammc@chromium.org

[commit-bot: I haz the power, 2016-05-12 06:29:23]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1975593003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1975593003/1

[commit-bot: I haz the power, 2016-05-12 07:54:16]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-05-12 07:55:59]

Description was changed from

==========
Run queued tasks before shutting down after running a layout test.

Currently, when a layout test run finishes, the BlinkTestController
falls out of scope, which triggers shutdown of the RenderProcessHostImpl
used by the test. However, RenderProcessHostImpl posts a task to delete
itself, which is currently never run; this results in a
RenderProcessHostImpl outliving the UI MessageLoop and its
BrowserContext, inviting use-after-frees. This CL fixes this issue by
running queued tasks before shutting down the main runner.

BUG=610989
==========

to

==========
Run queued tasks before shutting down after running a layout test.

Currently, when a layout test run finishes, the BlinkTestController
falls out of scope, which triggers shutdown of the RenderProcessHostImpl
used by the test. However, RenderProcessHostImpl posts a task to delete
itself, which is currently never run; this results in a
RenderProcessHostImpl outliving the UI MessageLoop and its
BrowserContext, inviting use-after-frees. This CL fixes this issue by
running queued tasks before shutting down the main runner.

BUG=610989

Committed: https://crrev.com/d8514447d66180f24e25713aea4445f80a9f4d6e
Cr-Commit-Position: refs/heads/master@{#393204}
==========

[commit-bot: I haz the power, 2016-05-12 07:56:00]

Patchset 1 (id:??) landed as
https://crrev.com/d8514447d66180f24e25713aea4445f80a9f4d6e
Cr-Commit-Position: refs/heads/master@{#393204}