Make AVD thread safe

This CL introduces staging properties to VectorDrawable, which holds
properties coming from UI thread. When staging properties are changed,
they are marked dirty, and the staging properties then get pushed to
RenderThread at sync point. In cases where no staging property has
been changed, at sync point we sync the render thread properties back
to staging properties to reflect the latest render thread animation
value change.

Also, update Vector Drawable bitmap only when it's dirty

Bug: 27343970
Bug: 27385912
Bug: 27263667
Bug: 27927674
Bug: 27774383

Change-Id: Ia864f5400a53a08dbfb284fae581fb1aac4fff87