Add Java properties for those XML attributes that don't have getter/setter
pairs. Also, link existing methods to their XML attributes where the comments
were previously missing.
This CL is worth extra scruitiny: first because it's View, and secondly
because many of the new APIs depend on subtleties in the underlying implementations
that I'm not familiar with.
Also, please consider whether it is too much to deprecate getBackgroundDrawable().
Change-Id: I0f2641926d86e5f44b92a0057736f64b59d2e9b9
6c8ea06abf