Fix DialogPlate transparency bug.

See bug for screenshot.

Bug: b:111596959
Change-Id: I96ebd18bcb7d4905df5e539a5ace36154e49c146
Reviewed-on: https://chromium-review.googlesource.com/1142225
Commit-Queue: David Black <dmblack@google.com>
Reviewed-by: Xiaohui Chen <xiaohuic@chromium.org>
Cr-Commit-Position: refs/heads/master@{#576186}
1 file changed