Revert of Make ui::Compositor use ui::Scheduler

Revert of Make ui::Compositor use ui::Scheduler (patchset #13 id:360001 of https://codereview.chromium.org/638653003/)

Reason for revert:
This appears to be causing crashes on the Windows perf bots.  See the linked bug for a stack trace.

BUG=439649
Original issue's description:
> Make ui::Compositor use ui::Scheduler
>
> Taken from enne's CL 535733002 and rebased. It has been taken out of CL 134623005.
>
> BUG=329552
>
> Committed: https://crrev.com/36b7fc7f8b05ea627873e58a162c1c26784e472d
> Cr-Commit-Position: refs/heads/master@{#298779}
>
> Committed: https://crrev.com/b821b71ff0166e250ae4b30b56c1b7b6d3bd5db6
> Cr-Commit-Position: refs/heads/master@{#306954}

TBR=ben@chromium.org,danakj@chromium.org,piman@chromium.org,sky@chromium.org,weiliangc@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=329552
Committed: https://crrev.com/4f0404e167031301c3f877e8000f5423b9adb9b7
Cr-Commit-Position: refs/heads/master@{#307132}

[Ilya Sherman, 2014-12-06 01:00:03]

Created Revert of Make ui::Compositor use ui::Scheduler

[commit-bot: I haz the power, 2014-12-06 01:00:38]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/784653002/1

[commit-bot: I haz the power, 2014-12-06 01:01:52]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2014-12-06 01:02:45]

Patchset 1 (id:??) landed as
https://crrev.com/4f0404e167031301c3f877e8000f5423b9adb9b7
Cr-Commit-Position: refs/heads/master@{#307132}