base

Use background drawable from the client

And set the drawable's callback to null during drag-resizing, since
we use multi-threaded renderer, will do not want to schedule draws
to the ViewRootImpl's thread.

bug: 26729953
Change-Id: I6e5f94a5a6ba15edc2d391dd11d8fee3c657d337
(cherry picked from commit 1cc95075e89a0f91cb59ff37a1a027199040c7b4)