SurfaceView: Make surfaceRedrawNeededAsync work with WM bypass.

Prior to SurfaceView bypassing the WM, the WM would see that
the app had multiple windows and wait for them all
to finish drawing before beginning any animation, or similar operations.
Now that SurfaceView is invisible to the WM we have to replicate this
two-way latching in ViewRootImpl.

Bug: 36492285
Test: Launch Chrome over and over.
Change-Id: Ie72c2d394f1bb0eb8551e6f63bb1c19a5df43afd