Revert of Web Animations: Defer cancellation of compositor animation until after compositing update (https://codereview.chromium.org/239453006/)

Reason for revert:
May introduce a leak.

http://build.chromium.org/p/chromium.webkit/builders/WebKit%20Linux%20Leak/builds/1384,

Original issue's description:
> Web Animations: Defer cancellation of compositor animation until after compositing update
> 
> Removes illegal compositing state queries.
> 
> BUG=339847
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=174779

TBR=dstockwell
BUG=377354,339847

Review URL: https://codereview.chromium.org/298103002

git-svn-id: svn://svn.chromium.org/blink/trunk@174784 bbb929c8-8fbe-4397-9dbb-9b2b20218538