Remote animations (app-controlled animations)

Adds the ability for another app to control an entire app
transition. It does so by creating an ActivityOptions object that
contains a RemoteAnimationAdapter object that describes how the
animation should be run: Along of some meta-data, this object
contains a callback that gets invoked from WM when the transition
is ready to be started.

Window manager supplies a list of RemoteAnimationApps into the
callback. Each app contains information about the app as well as
the animation leash. The controlling app can modify the leash like
any other surface, including the possibility to synchronize
updating the leash's surface properties with a frame to be drawn
using the Transaction.deferUntil API.

When the animation is done, the app can invoke the finished
callback to get WM out of the animating state, which will also
clean up any closing apps.

We use a timeout of 2000ms such that a buggy controlling app can
not break window manager forever (duration subject to change).

Test: go/wm-smoke
Test: RemoteAnimationControllerTest

Bug: 64674361
Change-Id: I34e0c9a91b28badebac74896f95c6390f1b947ab