SurfaceControlViewHostTests: Deflake touchable region test

ViewRootImpl propagates the touchable region to the window-manager
via a one-way call for which there is currently no way to wait
on the result. Rather than add something to the system-image
for this one test, we work around it by polling the dump. In
the future when we consolidate the client->WM interface we should
have a generic method of waiting on the completion of any
"Transaction", which can solve our problems around here.

Bug: 220765793
Test: SurfaceControlViewHostTests
Change-Id: I0ae9a48cd45685b4e4c9585521af9b86c0a9f057
1 file changed