Move the concept of Activation to the Shell.

ui/aura/client/aura_constants.cc

 // 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.
 
 #include "ui/aura/client/aura_constants.h"
 
 namespace aura {
 
 const char kAlwaysOnTopKey[] = "AlwaysOnTop";
 const char kRestoreBoundsKey[] = "RestoreBounds";
 const char kShowStateKey[] = "ShowState";
 const char kTooltipTextKey[] = "TooltipText";
 const char kModalKey[] = "Modal";
 const char kShadowTypeKey[] = "ShadowType";
 const char kRootWindowDragDropClientKey[] = "RootWindowDragDropClient";
 const char kDragDropDelegateKey[] = "DragDropDelegate";
 const char kRootWindowTooltipClientKey[] = "RootWindowTooltipClient";
+const char kRootWindowActiveWindow[] = "RootWindowActiveWindow";
+const char kRootWindowActivationClient[] = "RootWindowActivationClient";
+const char kActivationDelegateKey[] = "ActivationDelegate";
 
 }  // namespace aura