mash: Migrate MediaDelegate ownership and access to WmShell.

ash/common/wm_shell.cc

 // 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.
 
 #include "ash/common/wm_shell.h"
 
 #include "ash/common/focus_cycler.h"
 #include "ash/common/keyboard/keyboard_ui.h"
 #include "ash/common/shell_window_ids.h"
 #include "ash/common/system/chromeos/session/logout_confirmation_controller.h"
@@ skipping 43 matching lines @@
       }
     }
   }
   return false;
 }
 
 void WmShell::SetKeyboardUI(std::unique_ptr<KeyboardUI> keyboard_ui) {
   keyboard_ui_ = std::move(keyboard_ui);
 }
 
+void WmShell::SetMediaDelegate(std::unique_ptr<MediaDelegate> delegate) {
+  media_delegate_ = std::move(delegate);
+}
+
 void WmShell::SetSystemTrayDelegate(
     std::unique_ptr<SystemTrayDelegate> delegate) {
   DCHECK(delegate);
   DCHECK(!system_tray_delegate_);
   // TODO(jamescook): Create via ShellDelegate once it moves to //ash/common.
   system_tray_delegate_ = std::move(delegate);
   system_tray_delegate_->Initialize();
 #if defined(OS_CHROMEOS)
   logout_confirmation_controller_.reset(new LogoutConfirmationController(
       base::Bind(&SystemTrayDelegate::SignOut,
                  base::Unretained(system_tray_delegate_.get()))));
 #endif
 }
 
 void WmShell::DeleteSystemTrayDelegate() {
   DCHECK(system_tray_delegate_);
 #if defined(OS_CHROMEOS)
   logout_confirmation_controller_.reset();
 #endif
   system_tray_delegate_.reset();
 }
 
 void WmShell::DeleteWindowSelectorController() {
   window_selector_controller_.reset();
 }
 
 }  // namespace ash