Handle app custom icon via aura::Window property.

chrome/browser/ui/ash/launcher/app_window_launcher_item_controller.h

Index: chrome/browser/ui/ash/launcher/app_window_launcher_item_controller.h
diff --git a/chrome/browser/ui/ash/launcher/app_window_launcher_item_controller.h b/chrome/browser/ui/ash/launcher/app_window_launcher_item_controller.h
index e1fd8767a114e4be4af3debd6ca8c8b24f7e9e4c..456207801be8e255e3a75a852c09f1e22be35ddf 100644
--- a/chrome/browser/ui/ash/launcher/app_window_launcher_item_controller.h
+++ b/chrome/browser/ui/ash/launcher/app_window_launcher_item_controller.h
@@ -13,6 +13,8 @@
 #include "base/scoped_observer.h"
 #include "ui/aura/window_observer.h"
 
+class ChromeLauncherController;
+
 namespace aura {
 class Window;
 }
@@ -60,15 +62,11 @@ class AppWindowLauncherItemController : public ash::ShelfItemDelegate,
   // Activates the window at position |index|.
   void ActivateIndexedApp(size_t index);
 
-  // Called when launcher item may need to be updated, eg. label or icon.
-  // TODO(khmel): Use aura::Window property and observe property change
-  // http://crbug.com/724292
-  virtual void UpdateLauncherItem() {}
-
   const WindowList& windows() const { return windows_; }
 
  protected:
-  explicit AppWindowLauncherItemController(const ash::ShelfID& shelf_id);
+  AppWindowLauncherItemController(const ash::ShelfID& shelf_id,
+                                  ChromeLauncherController* owner);

[msw, 2017/06/01 19:47:28]

nit: just use ChromeLauncherController::instance() instead of injecting this
value. aside: Technically, CLC doesn't own ShelfItemDelegates, ShelfModel owns
them as ash::ShelfItemDelegates via ShelfModel::SetShelfItemDelegate.

[khmel, 2017/06/01 21:55:46]

Good point

 
   // Returns the action performed. Should be one of SHELF_ACTION_NONE,
   // SHELF_ACTION_WINDOW_ACTIVATED, or SHELF_ACTION_WINDOW_MINIMIZED.
@@ -84,9 +82,18 @@ class AppWindowLauncherItemController : public ash::ShelfItemDelegate,
   // Returns last active window in the controller or first window.
   ui::BaseWindow* GetLastActiveWindow();
 
+  ChromeLauncherController* owner() { return owner_; }
+
  private:
   WindowList::iterator GetFromNativeWindow(aura::Window* window);
 
+  // Handles the case when the app window in this controller has been changed,
+  // and sets the new controller icon based on currently active window.

[msw, 2017/06/01 19:47:28]

nit: "the currently"

[khmel, 2017/06/01 21:55:46]

Done.

+  void UpdateShelfItemIcon();
+
+  // Unowned pointer.
+  ChromeLauncherController* const owner_;
+
   // List of associated app windows
   WindowList windows_;