Revert of Animations: Port ProgrammaticScrollAnimator to use compositor timelines

Revert of Animations: Port ProgrammaticScrollAnimator to use compositor timelines (patchset #7 id:120001 of https://codereview.chromium.org/1133513002/)

Reason for revert:
Since this landed, 8 out of 9 runs of virtual/threaded_animation_timelines/fast/scroll-behavior/overflow-scroll-root-frame-animates.html have timed out on WebKit Linux MSAN:

http://test-results.appspot.com/dashboards/flakiness_dashboard.html#tests=virtual%2Fthreaded_animation_timelines%2Ffast%2Fscroll-behavior%2Foverflow-scroll-root-frame-animates.html

There has also been a timeout on WebKit Win Oilpan (dbg):

http://build.chromium.org/p/chromium.webkit/builders/WebKit%20Win%20Oilpan%20(dbg)/builds/1889

Original issue's description:
> Animations: Port ProgrammaticScrollAnimator to use compositor timelines
> 
> Use AnimationPlayer to add animations if new system enabled.
> 
> Previous episode: https://codereview.chromium.org/1119763003/
> What we want to achieve: https://codereview.chromium.org/1131833002
> 
> BUG=394777
> R=ajuma@chromium.org
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=199766

TBR=ajuma@chromium.org,vollick@chromium.org,loyso@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=394777
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=199815

[johnme, 2015-07-31 10:15:44]

Created Revert of Animations: Port ProgrammaticScrollAnimator to use compositor
timelines

[commit-bot: I haz the power, 2015-07-31 10:16:04]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1254963011/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1254963011/1

[commit-bot: I haz the power, 2015-07-31 10:17:00]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=199815

[johnme, 2015-07-31 10:48:33]

It also caused
virtual/threaded_animation_timelines/fast/scroll-behavior/main-frame-scrollBy.html
to timeout on Win (dbg):
http://test-results.appspot.com/dashboards/flakiness_dashboard.html#tests=vir...