The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/573b741e433a703670a80bbe43dea61b58238ba6

commit 573b741e433a703670a80bbe43dea61b58238ba6
Author: Renee Wright <rjwright@chromium.org>
Date: Wed May 16 02:29:38 2018

Make Crostini app icons focus existing window if already running

Currently if you click on the app list icon for Terminal or other
Crostini apps it always launches a new window. This change makes it so
that if the app is already running, the existing window is focused
instead of making a new one. It also adds a "new window" entry to the
context menu for Crostini apps' launcher icons, so that there is
still a way to get multiple windows of an app. (NB: new window
behavior differs by app. Xterm will launch multiple windows, Gedit will
add new tabs (Gedit tabs, not Chrome tabs), and VLC doesn't allow
multiple windows at all)


Bug:  839238 
Change-Id: I9f3c2ecdc4a5cf2faa9d32f43a8809851879ee4d
Reviewed-on: https://chromium-review.googlesource.com/1056893
Commit-Queue: Renée Wright <rjwright@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#558932}
[modify] https://crrev.com/573b741e433a703670a80bbe43dea61b58238ba6/chrome/browser/ui/app_list/crostini/crostini_app_item.cc
[modify] https://crrev.com/573b741e433a703670a80bbe43dea61b58238ba6/chrome/browser/ui/app_list/search/crostini_app_result.cc
[modify] https://crrev.com/573b741e433a703670a80bbe43dea61b58238ba6/chrome/browser/ui/ash/launcher/crostini_shelf_context_menu.cc
[modify] https://crrev.com/573b741e433a703670a80bbe43dea61b58238ba6/chrome/browser/ui/ash/launcher/crostini_shelf_context_menu.h

Quick thoughts, not sure if you'd rather re-open or file a new bug

- We need to also update the app context menu to support the new option.
- We may want to remove the "Open" item from the shelf context menu when an app is not open (or the New Window option?). Otherwise we have two entries that do the same and it looks a bit weird.