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

ash/display/root_window_transformers_unittest.cc

 // Copyright 2013 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/root_window_transformers.h"
 
 #include "ash/display/display_info.h"
 #include "ash/display/display_manager.h"
 #include "ash/magnifier/magnification_controller.h"
+#include "ash/host/root_window_transformer.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/cursor_manager_test_api.h"
 #include "ash/test/mirror_window_test_api.h"
 #include "base/synchronization/waitable_event.h"
 #include "ui/aura/env.h"
-#include "ui/aura/root_window_transformer.h"
 #include "ui/aura/test/event_generator.h"
 #include "ui/aura/window_event_dispatcher.h"
 #include "ui/aura/window_tracker.h"
 #include "ui/events/event_handler.h"
 #include "ui/gfx/display.h"
 #include "ui/gfx/rect_conversions.h"
 #include "ui/gfx/screen.h"
 #include "ui/views/widget/widget.h"
 
 namespace ash {
@@ skipping 362 matching lines @@
   Shell::GetInstance()->RemovePreTargetHandler(&event_handler);
 }
 
 TEST_F(RootWindowTransformersTest, LetterBoxPillarBox) {
   if (!SupportsMultipleDisplays())
     return;
   test::MirrorWindowTestApi test_api;
   DisplayManager* display_manager = Shell::GetInstance()->display_manager();
   display_manager->SetSecondDisplayMode(DisplayManager::MIRRORING);
   UpdateDisplay("400x200,500x500");
-  scoped_ptr<aura::RootWindowTransformer> transformer(
+  scoped_ptr<RootWindowTransformer> transformer(
       test_api.CreateCurrentRootWindowTransformer());
   // Y margin must be margin is (500 - 500/400 * 200) / 2 = 125.
   EXPECT_EQ("0,125,0,125", transformer->GetHostInsets().ToString());
 
   UpdateDisplay("200x400,500x500");
   // The aspect ratio is flipped, so X margin is now 125.
   transformer = test_api.CreateCurrentRootWindowTransformer();
   EXPECT_EQ("125,0,125,0", transformer->GetHostInsets().ToString());
 }
 
 }  // namespace test
 }  // namespace ash