Hook up the FocusController behind a flag.

ui/views/corewm/shadow_controller.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/corewm/shadow_controller.h"
 
 #include <utility>
 
 #include "base/command_line.h"
 #include "base/logging.h"
@@ skipping 49 matching lines @@
                   gaining_active);
     if (it != losing_active->transient_children().end())
       return Shadow::STYLE_ACTIVE;
   }
   return Shadow::STYLE_INACTIVE;
 }
 
 }  // namespace
 
 ShadowController::ShadowController(aura::RootWindow* root_window)
-    : ALLOW_THIS_IN_INITIALIZER_LIST(observer_manager_(this)),
+    : ActivationChangeShim(root_window),
+      ALLOW_THIS_IN_INITIALIZER_LIST(observer_manager_(this)),
       root_window_(root_window) {
   aura::Env::GetInstance()->AddObserver(this);
   // Watch for window activation changes.
   aura::client::GetActivationClient(root_window_)->AddObserver(this);
 }
 
 ShadowController::~ShadowController() {
   aura::client::GetActivationClient(root_window_)->RemoveObserver(this);
   aura::Env::GetInstance()->RemoveObserver(this);
 }
@@ skipping 76 matching lines @@
 
   shadow->Init(ShouldUseSmallShadowForWindow(window) ?
                Shadow::STYLE_SMALL : Shadow::STYLE_ACTIVE);
   shadow->SetContentBounds(gfx::Rect(window->bounds().size()));
   shadow->layer()->SetVisible(ShouldShowShadowForWindow(window));
   window->layer()->Add(shadow->layer());
 }
 
 }  // namespace corewm
 }  // namespace views