fix crostini app icon weirdness in SingleProcessMash

This CL made a short-term fix for crostini app icons when
SingleProcessMash is enabled. The observed problems are:
- the terminal app icon has the spinner (rotating cycle) on launch,
  but the spinner doesn't disappear when the terminal is ready
- other app icons (like gedit) create two app icons, one is the
  expected one and the other is the blank icon

The terminal app is a chrome app (hosted by browser), however
CrostiniAppWindowShelfController observes aura::Env in ash::Shell,
thus it will fail to obtain Browser object. It needs to aura::Env
in the browser.

The blank icon is created by ash::ShelfWindowWatcher; to prevent
this, kShelfItemTypeKey property needs to be set as
ArcAppWindowLauncherController does.

This is kinda hacky and does not work with multi-process Mash.
We will eventually need a major refactoring around the shelf and
the launcher.

Bug: 905802
Test: manually
Change-Id: If941bcc100160d3b5ff6e590032153000efc674a
Reviewed-on: https://chromium-review.googlesource.com/c/1371144
Commit-Queue: Jun Mukai <mukai@chromium.org>
Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#615983}

chrome/browser/ui/ash/launcher/crostini_app_window_shelf_controller.cc

@@ -69,17 +69,28 @@ CrostiniAppWindowShelfController::CrostiniAppWindowShelfController(
   // https://crbug.com/887156
   if (!features::IsMultiProcessMash())
     ash::Shell::Get()->aura_env()->AddObserver(this);
+  // When window service is enabled, aura::Env::GetInstance() is a different
+  // instance from ash::Shell::Get()->aura_env(), and it needs to be observed
+  // for the Crostini terminal, which is a Chrome app window. Note that it still
+  // needs to observe ash::Shell::Get()->aura_env() too for other crostini apps,
+  // which are hosted by exo.
+  // TODO(mukai): clean this up. https://crbug.com/887156
+  if (features::IsUsingWindowService())
+    aura::Env::GetInstance()->AddObserver(this);
 }
 
 CrostiniAppWindowShelfController::~CrostiniAppWindowShelfController() {
   for (auto* window : observed_windows_)
     window->RemoveObserver(this);
+  if (features::IsUsingWindowService())
+    aura::Env::GetInstance()->RemoveObserver(this);
   if (!features::IsMultiProcessMash())
     ash::Shell::Get()->aura_env()->RemoveObserver(this);
 }
 
 void CrostiniAppWindowShelfController::AddToShelf(aura::Window* window,
                                                   AppWindowBase* app_window) {
+  window->SetProperty<int>(ash::kShelfItemTypeKey, ash::TYPE_APP);
   ash::ShelfID shelf_id = app_window->shelf_id();
   AppWindowLauncherItemController* item_controller =
       owner()->shelf_model()->GetAppWindowLauncherItemController(shelf_id);