DO NOT MERGE Fix issue #6697105: App launching sometimes has random pauses

In the course of the window manager refactoring into a separate
layout state, we introduced a bad interaction between the two
sides of the world.  This resulting in multiple hops needed between
the two sides after an application has said it is finished drawing
its window, until the window/app transition is actually started.
Especially since these hops require going through the anim side
which is vsynced (so will delay its operation until the next frame),
this could introduce a notable delay until the window is first shown.

Fix this by re-arranging the code to make one straight path from
when a window reports it is shown to us starting the app transition
that is waiting for it.  This change also includes various improvements
to debugging code that was done while working on it.

Change-Id: I7883674052da1a58df89cd1d9b8d754843cdd3db