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This CL implements the needed changes for the toolbar buttons,
and the app menu button. The browser actions container will be
done in a follow-up CL.

BUG=818034

Change-Id: I0d8ec316aa98e553e77bef34d4ca120dd9c2f09f
Reviewed-on: https://chromium-review.googlesource.com/947385Reviewed-by: Evan Stade <estade@chromium.org>
Reviewed-by: Michael Wasserman <msw@chromium.org>
Reviewed-by: Peter Kasting <pkasting@chromium.org>
Commit-Queue: Ahmed Fakhry <afakhry@chromium.org>
Cr-Commit-Position: refs/heads/master@{#542242}