Eliminates all ash dependencies from WindowModalityController.

ash/wm/activation_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 "ash/wm/activation_controller.h"
 
 #include "ash/root_window_controller.h"
 #include "ash/shell.h"
 #include "ash/shell_window_ids.h"
 #include "ash/wm/activation_controller_delegate.h"
@@ skipping 192 matching lines @@
 
 void ActivationController::DeactivateWindow(aura::Window* window) {
   if (window)
     ActivateNextWindow(window);
 }
 
 aura::Window* ActivationController::GetActiveWindow() {
   return active_window_;
 }
 
+aura::Window* ActivationController::GetActivatableWindow(aura::Window* window) {
+  return GetActivatableWindow(window, NULL);
+}
+
 bool ActivationController::OnWillFocusWindow(aura::Window* window,
                                              const ui::Event* event) {
   return CanActivateWindowWithEvent(
       GetActivatableWindow(window, event), event, CURRENT_VISIBILITY);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // ActivationController, aura::WindowObserver implementation:
 
 void ActivationController::OnWindowVisibilityChanged(aura::Window* window,
@@ skipping 194 matching lines @@
   aura::Window* window = static_cast<aura::Window*>(event->target());
   window = delegate_->WillFocusWindow(window);
   if (GetActiveWindow() != window) {
     aura::client::GetFocusClient(window)->FocusWindow(
         FindFocusableWindowFor(window), event);
   }
 }
 
 }  // namespace internal
 }  // namespace ash