Fix FAB not returning after Snackbar dismissal

Caused by the fact that sometimes a removed view does
not trigger a onDependentViewChanged() dispatch. As
a removal doesn't really fit that method, I've added
a onDependentViewRemoved() call to Behavior.

BUG: 21799255
Change-Id: Ib86713a38928dfdbbfcf419e44bafe8023e5a8ee
3 files changed