Explicitly set scrim in location bar

Since the scrim is now created programmatically, it takes a bit of
extra time after chrome starts to be able to get access to it. In
the case of the location bar, its design allows users to focus it
prior to the rest of chrome being loaded. Because of this, it is
possible to get the omnibox focused without the scrim, locking up
the page under it. This change explicitly sets the scrim when it
becomes available in ChromeActivity and then calls the scrim update
method in case it is needed.

Bug: 850848
Change-Id: Ia0a25a0c6e8f9c2d64c914ebca5bbcf9e14601ad
Reviewed-on: https://chromium-review.googlesource.com/1101963
Commit-Queue: Matthew Jones <mdjones@chromium.org>
Reviewed-by: Ted Choc <tedchoc@chromium.org>
Cr-Commit-Position: refs/heads/master@{#568579}
6 files changed