Revert of Forward input and compositing tasks to the Blink scheduler

Revert of Forward input and compositing tasks to the Blink scheduler (patchset #21 id:400001 of https://codereview.chromium.org/363383002/)

Reason for revert:
13% regression on page load times.

BUG=411520
Original issue's description:
> Forward input and compositing tasks to the Blink scheduler
> 
> Instead of posting input and compositor tasks directly to the 
> main thread message loop, forward them to the Blink scheduler 
> so they can be prioritized over other tasks.
> 
> BUG=391005
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=290845
> 
> Committed: https://chromium.googlesource.com/chromium/src/+/68bab3290b45a8610ad875d3c92530477c16a948

TBR=jamesr@chromium.org,alexclarke@chromium.org,picksi@chromium.org,eseidel@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=391005
Committed: https://crrev.com/badb49abd63603974ed56c0971b62c8f599efa86
Cr-Commit-Position: refs/heads/master@{#293726}

[Sami, 2014-09-08 15:02:49]

Created Revert of Forward input and compositing tasks to the Blink scheduler

[commit-bot: I haz the power, 2014-09-08 15:04:11]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/skyostil@chromium.org/553483005/1

[commit-bot: I haz the power, 2014-09-08 15:06:00]

Committed patchset #1 (id:1) as 09da9136426c9e26f9d88ca3a61c042800991c2d

[commit-bot: I haz the power, 2014-09-10 03:46:19]

Patchset 1 (id:??) landed as
https://crrev.com/badb49abd63603974ed56c0971b62c8f599efa86
Cr-Commit-Position: refs/heads/master@{#293726}