Revert of cc: Control defer_commits logic by Scheduler

Revert of cc: Control defer_commits logic by Scheduler (patchset #12 id:250001 of https://codereview.chromium.org/337693005/)

Reason for revert:
seems to flakily not stop commits https://code.google.com/p/chromium/issues/detail?id=453787

Original issue's description:
> cc: Control defer_commits logic by Scheduler
>
> So far, EarlyOut_DeferCommits is controlled by Proxy.
> Because Scheduler doesn't know about this deferring, it triggers next
> BeginMainFrame when main thread want to defer a commit.
> This CL moves the EarlyOut_DeferCommits logic from Proxy to
> Scheduler so Scheduler can stop next BeginMainFrame until defer commit is off.
>
> R=brianderson@chromium.org, danakj@chromium.org, skyostil@chromium.org
> BUG=382572
> TEST=cc_unittests
>
> Committed: https://crrev.com/1625b74468e4dd55f54ba209f8e91d05493875b9
> Cr-Commit-Position: refs/heads/master@{#313816}

TBR=brianderson@chromium.org,skyostil@chromium.org,enne@chromium.org,mithro@mithis.com,simonhong@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=382572
Committed: https://crrev.com/06b3f03355d6fb783273eb4fd26e91830be2ce44
Cr-Commit-Position: refs/heads/master@{#313939}

[danakj, 2015-01-30 17:47:55]

Created Revert of cc: Control defer_commits logic by Scheduler

[commit-bot: I haz the power, 2015-01-30 17:49:12]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/870183004/1

[commit-bot: I haz the power, 2015-01-30 17:50:34]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-01-30 17:52:48]

Patchset 1 (id:??) landed as
https://crrev.com/06b3f03355d6fb783273eb4fd26e91830be2ce44
Cr-Commit-Position: refs/heads/master@{#313939}