GitLab

*Destroy old layer when new layer animation is aborted.
*Only log histograms once after animation.

The old layer is owned by a observer which does not know when the new
layer is being aborted. Change this so that the observer observers the
new layer and destroys the old layer accordingly.

The pass animations reporter will be used for every LayerAnimationElement,
for cross fade, we animate opacity in addition to transform when the old
bounds is wider than the new bounds. This results in double counting,
which skews the smoothness numbers as animating two properties should be
slower.

Test: manual, ash_unittests WindowAnimationsTest.CrossFadeHistograms
Bug: 868170, 1087460
Change-Id: I3bc5b597e8109a3e87f432f6aa352ba94860f8ed
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2218557Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Commit-Queue: Sammie Quon <sammiequon@chromium.org>
Cr-Commit-Position: refs/heads/master@{#773397}