Change FocusSynchronizer to maintain active focus client and window.

ui/aura/client/aura_constants.h

 // 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.
 
 #ifndef UI_AURA_CLIENT_AURA_CONSTANTS_H_
 #define UI_AURA_CLIENT_AURA_CONSTANTS_H_
 
 #include <string>
 
 #include "base/strings/string16.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "ui/aura/aura_export.h"
 #include "ui/aura/window.h"
 #include "ui/base/ui_base_types.h"
 
 namespace ui {
 namespace mojom {
 enum class WindowType;
 }
 }
 
 namespace aura {
 namespace client {
+class FocusClient;
 
 enum class WindowEmbedType {
   NONE,
   EMBED_IN_OWNER,
   TOP_LEVEL_IN_WM,
 };
 
 // Alphabetical sort.
 
 // A property key to store whether accessibility focus falls back to widget or
@@ skipping 21 matching lines @@
 // A property key to store if a window is a constrained window or not.
 AURA_EXPORT extern const WindowProperty<bool>* const kConstrainedWindowKey;
 
 // A property key to store if a window was created by a user gesture.
 AURA_EXPORT extern const WindowProperty<bool>* const kCreatedByUserGesture;
 
 // A property key to indicate that a window should show that it deserves
 // attention.
 AURA_EXPORT extern const WindowProperty<bool>* const kDrawAttentionKey;
 
+// A property key to store the focus client on the window.
+AURA_EXPORT extern const WindowProperty<FocusClient*>* const kFocusClientKey;
+
 // A property key to store the host window of a window. This lets
 // WebContentsViews find the windows that should constrain NPAPI plugins.
 AURA_EXPORT extern const WindowProperty<Window*>* const kHostWindowKey;
 
 // A property key to indicate that a window should be in immersive mode when the
 // window enters the fullscreen mode. The immersive fullscreen mode is slightly
 // different from the normal fullscreen mode by allowing the user to reveal the
 // top portion of the window through a touch / mouse gesture.
 AURA_EXPORT extern const WindowProperty<bool>* const kImmersiveFullscreenKey;
 
@@ skipping 54 matching lines @@
 
 AURA_EXPORT extern const WindowProperty<ui::mojom::WindowType>* const
     kWindowTypeKey;
 
 // Alphabetical sort.
 
 }  // namespace client
 }  // namespace aura
 
 #endif  // UI_AURA_CLIENT_AURA_CONSTANTS_H_