Convert AXAshWindowUtilsTest to SingleProcessMashTestBase

This eliminates some test setup boilerplate.

Bug: 911776
Test: ash_unittests
Change-Id: I3be7282776ed863031037d6059734f23ed38d303
Reviewed-on: https://chromium-review.googlesource.com/c/1379034
Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: James Cook <jamescook@chromium.org>
Cr-Commit-Position: refs/heads/master@{#616862}
1 file changed