Hook up the FocusController behind a flag.

ui/views/widget/native_widget_aura_window_observer.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/views/widget/native_widget_aura_window_observer.h"
 
 #include "ui/aura/client/activation_client.h"
 #include "ui/aura/root_window.h"
 #include "ui/aura/window.h"
 
 namespace views {
 
 NativeWidgetAuraWindowObserver::NativeWidgetAuraWindowObserver(
     gfx::NativeView native_view,
     internal::NativeWidgetDelegate* delegate)
-    : native_view_(native_view),
+    : ActivationChangeShim(native_view->GetRootWindow()),
+      native_view_(native_view),
       delegate_(delegate) {
   native_view_->GetRootWindow()->AddObserver(this);
   native_view_->AddObserver(this);
   aura::client::GetActivationClient(native_view_->GetRootWindow())->
       AddObserver(this);
 }
 
 NativeWidgetAuraWindowObserver::~NativeWidgetAuraWindowObserver() {
   CleanUpObservers();
 }
@@ skipping 17 matching lines @@
   if (!native_view_)
     return;
   native_view_->GetRootWindow()->RemoveObserver(this);
   native_view_->RemoveObserver(this);
   aura::client::GetActivationClient(native_view_->GetRootWindow())->
       RemoveObserver(this);
   native_view_ = NULL;
 }
 
 }  // namespace views