Inner bug: b/36265385

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/f4821feb1dfd4ad2b98ffc4be0c7deae02fa7e82

commit f4821feb1dfd4ad2b98ffc4be0c7deae02fa7e82
Author: khmel <khmel@chromium.org>
Date: Thu May 25 15:51:00 2017

arc: Set custom icon in shelf for ARC apps.

This handles setTaskDescription requests which provides optional icon
for the task. This CL receives icon from ARC and associates it with
ARC app window. ARC app window contoller receives updates and update
controller item accordingly. If no custom icon set then default app
icon is used.

Preview:
https://drive.google.com/a/google.com/file/d/0B63tZNwdjs-qM3FTYWVJdl9FMDA/view?usp=sharing

TEST=Manually + unit_test
BUG= 723742 

Review-Url: https://codereview.chromium.org/2894443002
Cr-Commit-Position: refs/heads/master@{#474663}

[modify] https://crrev.com/f4821feb1dfd4ad2b98ffc4be0c7deae02fa7e82/chrome/browser/ui/BUILD.gn
[modify] https://crrev.com/f4821feb1dfd4ad2b98ffc4be0c7deae02fa7e82/chrome/browser/ui/app_list/arc/arc_app_icon.cc
[modify] https://crrev.com/f4821feb1dfd4ad2b98ffc4be0c7deae02fa7e82/chrome/browser/ui/app_list/arc/arc_app_icon.h
[modify] https://crrev.com/f4821feb1dfd4ad2b98ffc4be0c7deae02fa7e82/chrome/browser/ui/app_list/arc/arc_app_list_prefs.cc
[modify] https://crrev.com/f4821feb1dfd4ad2b98ffc4be0c7deae02fa7e82/chrome/browser/ui/app_list/arc/arc_app_list_prefs.h
[modify] https://crrev.com/f4821feb1dfd4ad2b98ffc4be0c7deae02fa7e82/chrome/browser/ui/ash/launcher/app_window_launcher_item_controller.cc
[modify] https://crrev.com/f4821feb1dfd4ad2b98ffc4be0c7deae02fa7e82/chrome/browser/ui/ash/launcher/app_window_launcher_item_controller.h
[add] https://crrev.com/f4821feb1dfd4ad2b98ffc4be0c7deae02fa7e82/chrome/browser/ui/ash/launcher/arc_app_window.cc
[add] https://crrev.com/f4821feb1dfd4ad2b98ffc4be0c7deae02fa7e82/chrome/browser/ui/ash/launcher/arc_app_window.h
[modify] https://crrev.com/f4821feb1dfd4ad2b98ffc4be0c7deae02fa7e82/chrome/browser/ui/ash/launcher/arc_app_window_launcher_controller.cc
[modify] https://crrev.com/f4821feb1dfd4ad2b98ffc4be0c7deae02fa7e82/chrome/browser/ui/ash/launcher/arc_app_window_launcher_controller.h
[modify] https://crrev.com/f4821feb1dfd4ad2b98ffc4be0c7deae02fa7e82/chrome/browser/ui/ash/launcher/arc_app_window_launcher_item_controller.cc
[modify] https://crrev.com/f4821feb1dfd4ad2b98ffc4be0c7deae02fa7e82/chrome/browser/ui/ash/launcher/arc_app_window_launcher_item_controller.h
[modify] https://crrev.com/f4821feb1dfd4ad2b98ffc4be0c7deae02fa7e82/chrome/browser/ui/ash/launcher/chrome_launcher_controller_unittest.cc
[modify] https://crrev.com/f4821feb1dfd4ad2b98ffc4be0c7deae02fa7e82/components/arc/common/app.mojom
[modify] https://crrev.com/f4821feb1dfd4ad2b98ffc4be0c7deae02fa7e82/components/arc/test/fake_app_instance.cc
[modify] https://crrev.com/f4821feb1dfd4ad2b98ffc4be0c7deae02fa7e82/components/arc/test/fake_app_instance.h

This bug requires manual review: We are only 11 days from stable.
Please contact the milestone owner if you have questions.
Owners: amineer@(Android), cmasso@(iOS), gkihumba@(ChromeOS), Abdul Syed@(Desktop)

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

Consider high merge risk and this feature is not blocker for M59, moving target to M60. This code is actually there.