Refactor extension app icon.

chrome/browser/ui/app_icon_loader.h

 // Copyright 2016 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_APP_ICON_LOADER_H_
 #define CHROME_BROWSER_UI_APP_ICON_LOADER_H_
 
 #include <string>
 
 #include "base/macros.h"
 #include "chrome/browser/ui/app_icon_loader_delegate.h"
 
 class Profile;
 
 // Base class that loads and updates Chrome app's icons.
+// TODO(khmel): Switch to using ChromeAppIconService instead ChromeAppIconLoader
+// and ArcAppIconLoader.
 class AppIconLoader {
  public:
   virtual ~AppIconLoader();
 
   // Returns true is this AppIconLoader is able to load an image for the
   // requested app.
   virtual bool CanLoadImageForApp(const std::string& app_id) = 0;
 
   // Fetches the image for the specified id. When done (which may be
   // synchronous), this should invoke SetAppImage() on the delegate.
@@ skipping 21 matching lines @@
   Profile* const profile_ = nullptr;
   const int icon_size_ = 0;
 
   // The delegate object which receives the icon images. No ownership.
   AppIconLoaderDelegate* const delegate_ = nullptr;
 
   DISALLOW_COPY_AND_ASSIGN(AppIconLoader);
 };
 
 #endif  // CHROME_BROWSER_UI_APP_ICON_LOADER_H_