mash: Create system tray display and rotation lock items via delegate

ash/system/tray/system_tray.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_H_
 #define ASH_SYSTEM_TRAY_SYSTEM_TRAY_H_
 
 #include <map>
 #include <memory>
 #include <vector>
@@ skipping 33 matching lines @@
   ~SystemTray() override;
 
   // Calls TrayBackgroundView::Initialize(), creates the tray items, and
   // adds them to SystemTrayNotifier.
   void InitializeTrayItems(SystemTrayDelegate* delegate,
                            WebNotificationTray* web_notification_tray);
 
   // Resets internal pointers.
   void Shutdown();
 
-  // Adds a new item in the tray.
+  // Adds a new item in the tray. Takes ownership.
   void AddTrayItem(SystemTrayItem* item);

[James Cook, 2016/07/13 18:37:44]

I did not refactor this to take a std::unique_ptr because:
A) The function immediately sticks the |item| into ScopedVector |items_| and it
seemed wasteful to immediately release the pointer, and
B) Converting |items_| from ScopedVector to std::vector<std::unique_ptr> is not
a trivial conversion given how this class uses items_.get().  Probably
straightforward, but not trivial.

[msw, 2016/07/13 18:51:49]

Acknowledged.

 
-  // Removes an existing tray item.
-  void RemoveTrayItem(SystemTrayItem* item);
-
   // Returns all tray items that has been added to system tray.
   const std::vector<SystemTrayItem*>& GetTrayItems() const;
 
   // Shows the default view of all items.
   void ShowDefaultView(BubbleCreationType creation_type);
 
   // Shows default view that ingnores outside clicks and activation loss.
   void ShowPersistentDefaultView();
 
   // Shows details of a particular item. If |close_delay_in_seconds| is
@@ skipping 188 matching lines @@
   // A reference to the Screen share and capture item.
   ScreenTrayItem* screen_capture_tray_item_;  // not owned
   ScreenTrayItem* screen_share_tray_item_;    // not owned
 
   DISALLOW_COPY_AND_ASSIGN(SystemTray);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_TRAY_SYSTEM_TRAY_H_