Merged KeyButtonDrawable with tint drawable and shadow drawable (1/2)

KeyButtonDrawable can now draw its own shadow and tint based on its dark
intensity, no more shadow drawables wrapped by dual layer drawable and
cross fading to change their intensities. Refactored and simplified code
to get the nav bar drawables. AnimatedVectorDrawables can be used however
only dark intensity tinting will work on it. Fixed the clipped shadow in
landscape.

Change-Id: I6e234857f7972974aae34d92c7047086782124f0
Fixes: 112105450
Test: look at nav bar and tap rotate suggestion button