compositor: Reuse GetXDisplay() function from x11_util.h

ui/compositor/test/test_compositor_host.h

Index: ui/compositor/test/test_compositor_host.h
diff --git a/ui/compositor/test/test_compositor_host.h b/ui/compositor/test/test_compositor_host.h
index fc41d512b6f889512723fd9db6cbca55b6ca080d..67e7606c0616126f0635f27c46a5f3b13f003dce 100644
--- a/ui/compositor/test/test_compositor_host.h
+++ b/ui/compositor/test/test_compositor_host.h
@@ -1,12 +1,10 @@
-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Copyright 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.
 
 #ifndef UI_COMPOSITOR_TEST_TEST_COMPOSITOR_HOST_H_
 #define UI_COMPOSITOR_TEST_TEST_COMPOSITOR_HOST_H_
 
-#include "base/message_loop.h"
-
 namespace gfx {
 class Rect;
 }
@@ -25,7 +23,7 @@ class TestCompositorHost {
   // Shows the TestCompositorHost.
   virtual void Show() = 0;
 
-  virtual ui::Compositor* GetCompositor() = 0;
+  virtual Compositor* GetCompositor() = 0;
 };
 
 }  // namespace ui