Remove window/host accessors from WED; IWYU for WTH

ash/display/display_controller_unittest.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/display/display_controller.h"
 
 #include "ash/ash_switches.h"
 #include "ash/display/display_info.h"
 #include "ash/display/display_layout_store.h"
 #include "ash/display/display_manager.h"
 #include "ash/screen_util.h"
 #include "ash/shelf/shelf.h"
 #include "ash/shelf/shelf_widget.h"
 #include "ash/shell.h"
 #include "ash/test/ash_test_base.h"
 #include "ash/test/ash_test_helper.h"
 #include "ash/test/cursor_manager_test_api.h"
 #include "ash/test/display_manager_test_api.h"
 #include "ash/test/test_shell_delegate.h"
 #include "ash/wm/window_state.h"
 #include "ash/wm/wm_event.h"
 #include "base/command_line.h"
 #include "ui/aura/client/activation_change_observer.h"
 #include "ui/aura/client/activation_client.h"
 #include "ui/aura/client/focus_change_observer.h"
 #include "ui/aura/client/focus_client.h"
 #include "ui/aura/env.h"
 #include "ui/aura/test/event_generator.h"
-#include "ui/aura/window_event_dispatcher.h"
 #include "ui/aura/window_tracker.h"
+#include "ui/aura/window_tree_host.h"
 #include "ui/events/event_handler.h"
 #include "ui/gfx/display.h"
 #include "ui/gfx/screen.h"
 #include "ui/views/widget/widget.h"
 
 #if defined(USE_X11)
 #include <X11/Xlib.h>
 #include "ui/gfx/x/x11_types.h"
 #undef RootWindow
 #endif
@@ skipping 1354 matching lines @@
   EXPECT_EQ("aura_root_x", GetXWindowName(secondary->GetHost()));
 
   // Switching back to single display.
   UpdateDisplay("300x400");
   EXPECT_EQ("aura_root_0", GetXWindowName(
       Shell::GetPrimaryRootWindow()->GetHost()));
 }
 #endif
 
 }  // namespace ash