Synchronize dialog launch animations

This CL adds some synchronization to the dialog launch animation to
avoid flickering at the beginning and the end of the animation. It does
so by drawing the touch surface twice (in both the original window and
the dialog window) using a temporary ghost that is added/removed
before/after the animation.

I decided not to reuse the ghosts created by
GhostedViewLaunchAnimatorController because this would make this change
much more invasive, which I wanted to avoid given that the end goal is
to use BLAST synchronization instead of this CL.

Change-Id: Iac2eb2a2e78801a43847eebc72679c4952a73f1f
Bug: 193634619
Test: Manual