GitLab

 - use the correct icon for the desktop file for all channels
 - special case the desktop file name when running as a snap

Change-Id: I9e4d03a96754bd51d798a13d6476210b9f6a8ce2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2137328
Commit-Queue: Thomas Anderson <thomasanderson@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Reviewed-by: Thomas Anderson <thomasanderson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#758904}