Fix for AppBarLayout's scrolling view not laying out WIP

Caused by some logic in it's measure code which makes
it skip the measure if it's header hasn't been laid out.
For the first measure/layout pass this will always be
false so let's just assume that it has been measured.

BUG: 28742676
Change-Id: I72eec136983f9452e02ae6cda85de60918454748
1 file changed