Revert of Move DefaultActivationClient to wm/core

ui/aura/client/default_activation_client.h

Index: ui/aura/client/default_activation_client.h
diff --git a/ui/aura/client/default_activation_client.h b/ui/aura/client/default_activation_client.h
new file mode 100644
index 0000000000000000000000000000000000000000..47e19dbc561995cd3cb5a9a8fc27e1ffb274920b
--- /dev/null
+++ b/ui/aura/client/default_activation_client.h
@@ -0,0 +1,69 @@
+// Copyright 2013 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_DEFAULT_ACTIVATION_CLIENT_H_
+#define UI_AURA_CLIENT_DEFAULT_ACTIVATION_CLIENT_H_
+
+#include <vector>
+
+#include "base/compiler_specific.h"
+#include "base/logging.h"
+#include "base/observer_list.h"
+#include "ui/aura/aura_export.h"
+#include "ui/aura/window_observer.h"
+#include "ui/wm/public/activation_client.h"
+
+namespace aura {
+namespace client {
+class ActivationChangeObserver;
+}
+
+namespace client {
+
+// Simple ActivationClient implementation for use by tests and other targets
+// that just need basic behavior (e.g. activate windows whenever requested,
+// restack windows at the top when they're activated, etc.).
+class AURA_EXPORT DefaultActivationClient : public client::ActivationClient,
+                                            public WindowObserver {
+ public:
+  explicit DefaultActivationClient(Window* root_window);
+  virtual ~DefaultActivationClient();
+
+  // Overridden from client::ActivationClient:
+  virtual void AddObserver(client::ActivationChangeObserver* observer) OVERRIDE;
+  virtual void RemoveObserver(
+      client::ActivationChangeObserver* observer) OVERRIDE;
+  virtual void ActivateWindow(Window* window) OVERRIDE;
+  virtual void DeactivateWindow(Window* window) OVERRIDE;
+  virtual Window* GetActiveWindow() OVERRIDE;
+  virtual Window* GetActivatableWindow(Window* window) OVERRIDE;
+  virtual Window* GetToplevelWindow(Window* window) OVERRIDE;
+  virtual bool OnWillFocusWindow(Window* window,
+                                 const ui::Event* event) OVERRIDE;
+  virtual bool CanActivateWindow(Window* window) const OVERRIDE;
+
+  // Overridden from WindowObserver:
+  virtual void OnWindowDestroyed(Window* window) OVERRIDE;
+
+ private:
+  void RemoveActiveWindow(Window* window);
+
+  // This class explicitly does NOT store the active window in a window property
+  // to make sure that ActivationChangeObserver is not treated as part of the
+  // aura API. Assumptions to that end will cause tests that use this client to
+  // fail.
+  std::vector<Window*> active_windows_;
+
+  // The window which was active before the currently active one.
+  Window* last_active_;
+
+  ObserverList<client::ActivationChangeObserver> observers_;
+
+  DISALLOW_COPY_AND_ASSIGN(DefaultActivationClient);
+};
+
+}  // namespace client
+}  // namespace aura
+
+#endif  // UI_AURA_CLIENT_DEFAULT_ACTIVATION_CLIENT_H_