Hand off gesture nav animations to registered remotes.

This is in support of long-lived return animations in the Animation
library. Sometimes we want the home gesture to minimize the
foreground app into a custom view other than the default Launcher
behavior.

For example, ongoing call will minimize to the status bar chip, even if
the app icon is on Home. This is guaranteed to be handled is the
takeover handler is not null, and only happens in this case (which means
a custom animation has been registered and is ready to run).

Bug: 323863002
Bug: 202516970
Flag: com.android.systemui.shared.return_animation_framework_library
Flag: com.android.systemui.shared.return_animation_framework_long_lived
Test: manual and unit test included
Change-Id: Id7cd1f6e92ad3cbe3c259b3f80c753c91472b455
6 files changed