GitLab

https://crrev.com/c/2590646 fixes the problem by observing
Layer directly. It introduces flakiness in ScreenRotationPerf.
The screen rotation animates two copied layers and the layers
could be destroyed before the reports are received. When that
happens, the metric is not recorded.

The root cause of the leak problem is AnimationTracker retains
LayerAnimator. When underlying Layer is gone, animations
are still owned by LayerAnimator and not aborted. Thus,
AnimationTracker still thinks it has animations to track.

This CL essentially reverts https://crrev.com/c/2590646 and
fix the leaking problem by make AnimationTracker not retain
LayerAnimator. This allows the animator being destroyed with
its layer and the animation callbacks to happen. As a result,
HasAnimationsToTrack would correctly return whether there are
animations to track when reporter goes away.

BUG=1162167, 1158510

Change-Id: Ie2a8191c1abbbc9e57b42090f66014f43fa62bc0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2618518Reviewed-by: kylechar <kylechar@chromium.org>
Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Commit-Queue: Xiyuan Xia <xiyuan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#842202}