Change FocusSynchronizer to maintain active focus client and window.

ui/aura/client/focus_client.cc

 // Copyright (c) 2012 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 "ui/aura/client/focus_client.h"
 
+#include "ui/aura/client/aura_constants.h"
 #include "ui/aura/window_event_dispatcher.h"
 #include "ui/base/class_property.h"
 
-DECLARE_EXPORTED_UI_CLASS_PROPERTY_TYPE(AURA_EXPORT, aura::client::FocusClient*)
-
 namespace aura {
 namespace client {
 
-DEFINE_UI_CLASS_PROPERTY_KEY(FocusClient*, kFocusClientKey, nullptr);
-
 void SetFocusClient(Window* root_window, FocusClient* client) {
   DCHECK_EQ(root_window->GetRootWindow(), root_window);
   root_window->SetProperty(kFocusClientKey, client);
 }
 
 FocusClient* GetFocusClient(Window* window) {
   return GetFocusClient(static_cast<const Window*>(window));
 }
 
 FocusClient* GetFocusClient(const Window* window) {
   const Window* root_window = window->GetRootWindow();
   return root_window ? root_window->GetProperty(kFocusClientKey) : nullptr;
 }
 
 }  // namespace client
 }  // namespace aura