r76372 separated context flushing from rendering, but this bit of code got left behind.

Reviewed by Sam Weinig.

* platform/graphics/ca/win/CACFLayerTreeHost.cpp:
(WebCore::CACFLayerTreeHost::render): Moved code to notify the layers from here to
notifyAnimationsStarted.
(WebCore::CACFLayerTreeHost::flushPendingLayerChangesNow): Added a call to
notifyAnimationsStarted after we flush the context.
(WebCore::CACFLayerTreeHost::notifyAnimationsStarted): Added. Code came from render. Changed
to call PlatformCALayer::animationStarted rather than calling through to the client
directly.

* platform/graphics/ca/win/CACFLayerTreeHost.h: Added notifyAniamtionsStarted.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@76762 268f45cc-cd09-0410-ab3c-d52691b4dbfc