[renderer]: Fix RendererScheduler shutdown logic to ensure it is shutdown before the MessageLoop.

[renderer]: Fix RendererScheduler shutdown logic to ensure it is shutdown before the MessageLoop.

The RendererScheduler needs to be shutdown before the MessageLoop. Previously
this was the case as blink was shutdown before the message loop, however now
the message loop is shutdown first. This CL ensures that the renderer
scheduler is shutdown just before the message loop.

BUG=467369
Committed: https://crrev.com/168f3dccd82fc0274ac3f573f1607d23b3fe8181
Cr-Commit-Position: refs/heads/master@{#320908}

[rmcilroy, 2015-03-16 18:23:38]

rmcilroy@chromium.org changed reviewers:
+ jochen@chromium.org, skyostil@chromium.org

[rmcilroy, 2015-03-16 18:23:39]

jochen@chromium.org: Please review changes in renderer_main.cc

skyostil@chromium.org: Please review changes in web_scheduler_impl.cc

Blink side of the change at: https://codereview.chromium.org/1011693003

[Sami, 2015-03-16 19:10:21]

Thanks, lgtm % trybots passing :)

[jochen (gone - plz use gerrit), 2015-03-17 10:30:39]

lgtm

[rmcilroy, 2015-03-17 10:47:12]

The CQ bit was checked by rmcilroy@chromium.org

[commit-bot: I haz the power, 2015-03-17 10:47:27]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1014643002/1

[commit-bot: I haz the power, 2015-03-17 13:09:21]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-03-17 13:15:58]

Patchset 1 (id:??) landed as
https://crrev.com/168f3dccd82fc0274ac3f573f1607d23b3fe8181
Cr-Commit-Position: refs/heads/master@{#320908}