Allow CoordinatorLayout to handle root level pkg

Currently CoordinatorLayout assumes that it will have a
parent package. This might not happen though with
Proguard involved. This CL makes CoL more defensive
over the package name.

BUG: 24701447

Change-Id: I391466b2e3b8f6d3d332a76dde6125b1eddd4156
1 file changed