Move ActivationClient/Delegate to client namespace.

ui/aura/client/activation_client.h

 // Copyright (c) 2011 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 UI_AURA_CLIENT_ACTIVATION_CLIENT_H_
 #define UI_AURA_CLIENT_ACTIVATION_CLIENT_H_
 #pragma once
 
 #include "ui/aura/aura_export.h"
 
 namespace aura {
-
 class Window;
+namespace client {
 
 // An interface implemented by an object that manages window activation.
 class AURA_EXPORT ActivationClient {
  public:
-  // Sets/Gets the activation client on the RootWindow.
-  static void SetActivationClient(ActivationClient* client);
-  static ActivationClient* GetActivationClient();
-
   // Activates |window|. If |window| is NULL, nothing happens.
   virtual void ActivateWindow(Window* window) = 0;
 
   // Deactivates |window|. What (if anything) is activated next is up to the
   // client. If |window| is NULL, nothing happens.
   virtual void DeactivateWindow(Window* window) = 0;
 
   // Retrieves the active window, or NULL if there is none.
   virtual aura::Window* GetActiveWindow() = 0;
 
   // Returns true if |window| can be focused. To be focusable, |window| must
   // exist inside an activatable window.
   virtual bool CanFocusWindow(Window* window) const = 0;
 
  protected:
   virtual ~ActivationClient() {}
 };
 
+// Sets/Gets the activation client on the RootWindow.
+AURA_EXPORT void SetActivationClient(ActivationClient* client);
+AURA_EXPORT ActivationClient* GetActivationClient();
+
+}  // namespace clients
 }  // namespace aura
 
 #endif  // UI_AURA_CLIENT_ACTIVATION_CLIENT_H_