Move the concept of Activation to the Shell.

ui/aura/client/activation_delegate.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_DELEGATE_H_
+#define UI_AURA_CLIENT_ACTIVATION_DELEGATE_H_
+#pragma once
+
+#include "ui/aura/aura_export.h"
+
+namespace aura {
+
+class Event;
+class Window;
+
+// An interface implemented by an object that configures and responds to changes
+// to a window's activation state.
+class AURA_EXPORT ActivationDelegate {
+ public:
+  // Sets/Gets the ActivationDelegate on the Window. No ownership changes.
+  static void SetActivationDelegate(Window* window,
+                                    ActivationDelegate* delegate);
+  static ActivationDelegate* GetActivationDelegate(Window* window);
+
+  // Returns true if the window should be activated. |event| is either the mouse
+  // event supplied if the activation is the result of a mouse, or the touch
+  // event if the activation is the result of a touch, or NULL if activation is
+  // attempted for another reason.
+  virtual bool ShouldActivate(Event* event) = 0;
+
+  // Sent when the window is activated.
+  virtual void OnActivated() = 0;
+
+  // Sent when the window loses active status.
+  virtual void OnLostActive() = 0;
+
+ protected:
+  virtual ~ActivationDelegate() {}
+};
+
+}  // namespace aura
+
+#endif  // UI_AURA_CLIENT_ACTIVATION_DELEGATE_H_