ActivityView animations!

Expand/collapse animations work by applying a matrix to the expanded view container - this is a) fast b) allows for pivot scale animation c) works around some weirdness with "actually" scaling the view, since the matrix transform is applied after the AV draws.

Switch animations work by snapshotting the current bubble's surface into graphics memory, rendering that into a SurfaceView, and animating the SurfaceView out. Memory profiler indicates this does not use additional memory (since those pixels were already in graphic memory anyway, and released as soon as the animation ends).

Test: lots and lots of manual testing
Fixes: 123306815
Fixes: 135137761
Merged-In: I0b01dab4bb0c82873afc55d054bafc672bacc8bf
Change-Id: I0b01dab4bb0c82873afc55d054bafc672bacc8bf