Fix crash due to animationDidEnd called on deallocated RemoteLayerTreeHost
https://bugs.webkit.org/show_bug.cgi?id=148442
<rdar://problem/
21609257>
Reviewed by Tim Horton.
A PlatformCAAnimationRemote's backpointer to a deallocated RemoteLayerTreeHost is not
invalidated when its host removes its reference to it.
* UIProcess/mac/RemoteLayerTreeHost.mm:
(WebKit::RemoteLayerTreeHost::layerWillBeRemoved): Invalidate a backpointer from the
PlatformCAAnimationRemotes to the RemoteLayerTreeHost.
git-svn-id: https://svn.webkit.org/repository/webkit/trunk@188991
268f45cc-cd09-0410-ab3c-
d52691b4dbfc