mash: Migrate wallpaper controllers to ash/common.

ash/mus/bridge/wm_shell_mus.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 ASH_MUS_BRIDGE_WM_SHELL_MUS_H_
 #define ASH_MUS_BRIDGE_WM_SHELL_MUS_H_
 
 #include <stdint.h>
 
 #include <memory>
 #include <vector>
 
 #include "ash/common/wm_shell.h"
 #include "base/macros.h"
 #include "base/observer_list.h"
+#include "base/threading/sequenced_worker_pool.h"
 #include "services/ui/public/cpp/window_tree_client_observer.h"
 
 namespace shell {
 class Connector;
 }
 
 namespace ui {
 class WindowTreeClient;
 }
 
@@ skipping 79 matching lines @@
   void OnOverviewModeEnded() override;
   SessionStateDelegate* GetSessionStateDelegate() override;
   void AddActivationObserver(WmActivationObserver* observer) override;
   void RemoveActivationObserver(WmActivationObserver* observer) override;
   void AddDisplayObserver(WmDisplayObserver* observer) override;
   void RemoveDisplayObserver(WmDisplayObserver* observer) override;
   void AddPointerWatcher(views::PointerWatcher* watcher,
                          views::PointerWatcherEventTypes events) override;
   void RemovePointerWatcher(views::PointerWatcher* watcher) override;
   bool IsTouchDown() override;
+  base::SequencedWorkerPool* GetBlockingPool() override;
 #if defined(OS_CHROMEOS)
   void ToggleIgnoreExternalKeyboard() override;
 #endif
 
  private:
   friend class WmShellMusTestApi;
 
   ui::WindowTreeClient* window_tree_client();
 
   // Returns true if |window| is a window that can have active children.
@@ skipping 12 matching lines @@
 
   std::unique_ptr<AcceleratorControllerDelegateMus>
       accelerator_controller_delegate_;
   std::unique_ptr<AcceleratorControllerRegistrar>
       accelerator_controller_registrar_;
   std::unique_ptr<ImmersiveHandlerFactoryMus> immersive_handler_factory_;
   std::unique_ptr<SessionStateDelegate> session_state_delegate_;
 
   base::ObserverList<WmActivationObserver> activation_observers_;
 
+  scoped_refptr<base::SequencedWorkerPool> blocking_pool_;
+
   DISALLOW_COPY_AND_ASSIGN(WmShellMus);
 };
 
 }  // namespace mus
 }  // namespace ash
 
 #endif  // ASH_MUS_BRIDGE_WM_SHELL_MUS_H_