cc: Alow animations to be aborted from either thread

This makes LayerAnimationController correctly handle animations that are
aborted on the compositor thread. It also adds an AbortAnimations method that
aborts all animations with a particular target property.

These changes are needed for implementing the CSSOM View smooth scroll API,
since we will require the ability to abort scroll animations on the
compositor thread as a result of input events received by the compositor
thread.

BUG=243871

Review URL: https://codereview.chromium.org/68503014

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@235557 0039d316-1c4b-4281-b951-d872f2087c98
5 files changed