Handle app custom icon via aura::Window property.

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

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_UI_ASH_LAUNCHER_APP_WINDOW_LAUNCHER_ITEM_CONTROLLER_H_
 #define CHROME_BROWSER_UI_ASH_LAUNCHER_APP_WINDOW_LAUNCHER_ITEM_CONTROLLER_H_
 
 #include <list>
 #include <string>
 
 #include "ash/public/cpp/shelf_item_delegate.h"
 #include "base/macros.h"
 #include "base/scoped_observer.h"
 #include "ui/aura/window_observer.h"
 
+class ChromeLauncherController;
+
 namespace aura {
 class Window;
 }
 
 namespace ui {
 class BaseWindow;
 }
 
 // This is a ShelfItemDelegate for abstract app windows (extension or ARC).
 // There is one instance per app, per launcher id. For apps with multiple
@@ skipping 27 matching lines @@
   void OnWindowPropertyChanged(aura::Window* window,
                                const void* key,
                                intptr_t old) override;
 
   // Get the number of running applications/incarnations of this.
   size_t window_count() const { return windows_.size(); }
 
   // 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);
 
   // Returns the action performed. Should be one of SHELF_ACTION_NONE,
   // SHELF_ACTION_WINDOW_ACTIVATED, or SHELF_ACTION_WINDOW_MINIMIZED.
   ash::ShelfAction ShowAndActivateOrMinimize(ui::BaseWindow* window);
 
   // Activate the given |window_to_show|, or - if already selected - advance to
   // the next window of similar type.
   // Returns the action performed. Should be one of SHELF_ACTION_NONE,
   // SHELF_ACTION_WINDOW_ACTIVATED, or SHELF_ACTION_WINDOW_MINIMIZED.
   ash::ShelfAction ActivateOrAdvanceToNextAppWindow(
       ui::BaseWindow* window_to_show);
 
   // Returns last active window in the controller or first window.
   ui::BaseWindow* GetLastActiveWindow();
 
+  ChromeLauncherController* owner() { return owner_; }
+
  private:
   WindowList::iterator GetFromNativeWindow(aura::Window* window);
 
+  void UpdateLauncherItem();

[msw, 2017/05/23 00:02:29]

nit: comment (or inline in OnWindowPropertyChanged), rename UpdateShelfItemIcon?

[khmel, 2017/05/23 16:11:43]

Done. Inlining is not very possible because it is called not only on prop change
but also when active window is changed (case multiple windows in one
controller).

+
+  // Unowned pointer.
+  ChromeLauncherController* const owner_;
+
   // List of associated app windows
   WindowList windows_;
 
   // Pointer to the most recently active app window
   // TODO(khmel): Get rid of |last_active_window_| and provide more reliable
   // way to determine active window.
   ui::BaseWindow* last_active_window_ = nullptr;
 
   // Scoped list of observed windows (for removal on destruction)
   ScopedObserver<aura::Window, aura::WindowObserver> observed_windows_;
 
   DISALLOW_COPY_AND_ASSIGN(AppWindowLauncherItemController);
 };
 
 #endif  // CHROME_BROWSER_UI_ASH_LAUNCHER_APP_WINDOW_LAUNCHER_ITEM_CONTROLLER_H_