Introdcue AshWindowTreeHost and move ash/chrome specific code in WTH to ash.

ash/test/test_shell_delegate.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/test/test_shell_delegate.h"
 
 #include <limits>
 
 #include "ash/default_accessibility_delegate.h"
 #include "ash/gpu_support_stub.h"
-#include "ash/host/window_tree_host_factory.h"
 #include "ash/media_delegate.h"
 #include "ash/new_window_delegate.h"
 #include "ash/session_state_delegate.h"
 #include "ash/shell.h"
 #include "ash/shell/keyboard_controller_proxy_stub.h"
 #include "ash/shell_window_ids.h"
 #include "ash/test/test_session_state_delegate.h"
 #include "ash/test/test_shelf_delegate.h"
 #include "ash/test/test_system_tray_delegate.h"
 #include "ash/test/test_user_wallpaper_delegate.h"
@@ skipping 124 matching lines @@
   return new MediaDelegateImpl;
 }
 
 ui::MenuModel* TestShellDelegate::CreateContextMenu(
     aura::Window* root,
     ash::ShelfItemDelegate* item_delegate,
     ash::ShelfItem* item) {
   return NULL;
 }
 
-WindowTreeHostFactory* TestShellDelegate::CreateWindowTreeHostFactory() {
-  return WindowTreeHostFactory::Create();
-}
-
 GPUSupport* TestShellDelegate::CreateGPUSupport() {
   // Real GPU support depends on src/content, so just use a stub.
   return new GPUSupportStub;
 }
 
 base::string16 TestShellDelegate::GetProductName() const {
   return base::string16();
 }
 
 TestSessionStateDelegate* TestShellDelegate::test_session_state_delegate() {
   return test_session_state_delegate_;
 }
 
 }  // namespace test
 }  // namespace ash