Replace the temporary app icon with the finalized app icon.

Bug: 1059779
Change-Id: I6105da8922cb0ccc0ac40c9fe061ebdb8ec9a44a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2486480Reviewed-by: Giovanni Ortuño Urquidi <ortuno@chromium.org>
Commit-Queue: Jesse Schettler <jschettler@chromium.org>
Cr-Commit-Position: refs/heads/master@{#819387}