Added the possibility to animate X and refactoring

A viewstate can now animate its X value.
This also refactors the animation logic such that
an application when an animation is running will
update the existing animation nicely.

Test: manual, observe views animating in X
Bug: 32437839
Change-Id: Ic091d87e530af793281ca3f2b1e9370ff5dac236
4 files changed