Add UI for cast system tray integration

ash/system/tray/system_tray_item.h

 // Copyright (c) 2012 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 ASH_SYSTEM_TRAY_SYSTEM_TRAY_ITEM_H_
 #define ASH_SYSTEM_TRAY_SYSTEM_TRAY_ITEM_H_
 
 #include "ash/ash_export.h"
 #include "ash/shelf/shelf_types.h"
 #include "ash/system/user/login_status.h"
@@ skipping 17 matching lines @@
   // type of view. The default implementations return NULL.
 
   // Returns a view to be displayed in the system tray. If this returns NULL,
   // then this item is not displayed in the tray.
   // NOTE: The returned view should almost always be a TrayItemView, which
   // automatically resizes the widget when the size of the view changes, and
   // adds animation when the visibility of the view changes. If a view wants to
   // avoid this behavior, then it should not be a TrayItemView.
   virtual views::View* CreateTrayView(user::LoginStatus status);
 
-  // Returns a view for the item to be displayed in the list. This view can be
-  // displayed with a number of other tray items, so this should not be too
-  // big.
+  // Returns a view for the item to be displayed in the popup list after
+  // clicking the system tray. This view can be displayed with a number of other
+  // tray items, so this should not be too big.
   virtual views::View* CreateDefaultView(user::LoginStatus status);
 
   // Returns a detailed view for the item. This view is displayed standalone.
   virtual views::View* CreateDetailedView(user::LoginStatus status);
 
   // Returns a notification view for the item. This view is displayed with
   // other notifications and should be the same size as default views.
   virtual views::View* CreateNotificationView(user::LoginStatus status);
 
   // These functions are called when the corresponding view item is about to be
@@ skipping 61 matching lines @@
  private:
   SystemTray* system_tray_;
   bool restore_focus_;
 
   DISALLOW_COPY_AND_ASSIGN(SystemTrayItem);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_TRAY_SYSTEM_TRAY_ITEM_H_