As part of the permission dialog work, I want to make sure that the
icon displayed in the dialog matches that of the Chrome app and other
clients (instead of the older icon which had two blue rectangles).

The concern is that the outdated icon may make the dialog look less
trustworthy and users might dismiss it outright instead of reading it.

Bug: 902041, 757618
Change-Id: Ia69ea7dab6d7d246302b75b199831c4048935888
Reviewed-on: https://chromium-review.googlesource.com/c/1336058
Commit-Queue: Joe Downing <joedow@chromium.org>
Reviewed-by: Jamie Walch <jamiewalch@chromium.org>
Cr-Commit-Position: refs/heads/master@{#608069}