Dispatch transitioncancel event if transition animation is interrupted.

In order to dispatch transitioncancel we need to allow dispatching events for
non animation frame timing updates as a canceled transition does not run on
the next frame.

Bug: 642487
Change-Id: I1225b60dc1666d5f225f9ddff1b3f9603b1b378b
Reviewed-on: https://chromium-review.googlesource.com/c/1450047
Commit-Queue: Robert Flack <flackr@chromium.org>
Reviewed-by: Stephen McGruer <smcgruer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#629590}
7 files changed