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

ash/wm/window_manager_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/shell.h"
 #include "ash/shell_window_ids.h"
 #include "ash/test/ash_test_base.h"
 #include "ash/test/shell_test_api.h"
 #include "ash/test/test_activation_delegate.h"
 #include "ash/wm/window_util.h"
@@ skipping 586 matching lines @@
   aura::Window* root_window = Shell::GetPrimaryRootWindow();
   gfx::Size size = root_window->bounds().size();
   EXPECT_EQ(gfx::Rect(size).ToString(),
             Shell::GetScreen()->GetDisplayNearestPoint(
                 gfx::Point()).bounds().ToString());
 
   // Rotate it clock-wise 90 degrees.
   gfx::Transform transform;
   transform.Translate(size.width(), 0);
   transform.Rotate(90.0f);
-  root_window->GetHost()->SetTransform(transform);
+  root_window->GetHost()->SetRootTransform(transform);
 
   test::TestActivationDelegate d1;
   aura::test::TestWindowDelegate wd;
   scoped_ptr<aura::Window> w1(
       CreateTestWindowInShellWithDelegate(&wd, 1, gfx::Rect(0, 15, 50, 50)));
   d1.SetWindow(w1.get());
   w1->Show();
 
   gfx::Point miss_point(5, 5);
   transform.TransformPoint(&miss_point);
@@ skipping 214 matching lines @@
   observer_a.reset();
   observer_b.reset();
   generator.MoveMouseTo(50, 50);
   EXPECT_TRUE(observer_a.did_visibility_change());
   EXPECT_FALSE(observer_b.did_visibility_change());
   EXPECT_TRUE(observer_a.is_cursor_visible());
 }
 #endif  // defined(OS_CHROMEOS)
 
 }  // namespace ash