GitLab

Use AppCompatButton in modal_dialog_view so that the text appearance
can be applied to pre L devices.

Bug: 872212
Change-Id: Ib84be209d086306983267cff5be0151202093ad6
Reviewed-on: https://chromium-review.googlesource.com/1173450
Commit-Queue: Becky Zhou <huayinz@chromium.org>
Reviewed-by: Theresa <twellington@chromium.org>
Cr-Commit-Position: refs/heads/master@{#583337}