[webkit-reviews] review requested: [Bug 83179] [chromium] Race condition in CCLayerTreeHostTestSynchronizeAnimationStartTimes : [Attachment 135648] Patch

[bugzilla-daemon at webkit.org]

vollick at chromium.org has asked	for review:
Bug 83179: [chromium] Race condition in
CCLayerTreeHostTestSynchronizeAnimationStartTimes
https://bugs.webkit.org/show_bug.cgi?id=83179

Attachment 135648: Patch
https://bugs.webkit.org/attachment.cgi?id=135648&action=review

------- Additional Comments from vollick at chromium.org
Before the call to notifyAnimationStarted, we must have a valid
layerTreeHostImpl
or else we won't be able to compare the start times of the animations.
Previously,
we'd grabbed this value in TestHooks::animateLayers. This function is called on
the impl thread _after_ the call to CCLayerTreeHostImpl::animateLayers. The
problem
is that we check this value in notifyAnimationStarted which executes on the
main
thread, possibly before TestHooks::animateLayers. To get around this problem,
we
grab the pointer to the layerTreeHostImpl in willAnimateLayers instead. This is
guaranteed to be called before notifyAnimationStarted (notifyAnimationStarted
is
called due to a task posted by CCLayerTreeHostImpl::animateLayers, which is
called after willAnimateLayers).