Add AppCompatResources.getDrawable()

This CL adds the new public method, which just
proxies to AppCompatDrawableManager for now. Also
moved all internal calls of
AppCompatDrawableManager.getDrawable() to the new method.

Looks like a huge commit, but it's mostly just moving
things to use the new method.

BUG: 29564497
Change-Id: Ie1603cc83d58333d70b90aefcfaf21fd367081ae
37 files changed