Bug: 17372309
AnimationContext::startFrame() happens both with and without
the UI thread lock. Pass the TraversalMode into it so
that ThreadedRenderer's subclass can correctly decide
when it is safe to push over mPendingAnimatingRenderNodes, as doing
so outside of the lock is Very Bad.
Change-Id: Ife5dd3a2b46b0a207cd9234c159a674afdbf5efd
Bug: 17372309
Fixes a case where UI thread and RT thread both used the same method
which wasn't safe for either of them.
Adds additional assertions & logging in unusual circumstances to
try and track down where the issue is occuring from.
Change-Id: I93d31a6fd0c5927259b67bdf96a475944226eee6
