aura-mus: Remove dead code.

ui/aura/mus/mus_util.h

Index: ui/aura/mus/mus_util.h
diff --git a/ui/aura/mus/mus_util.h b/ui/aura/mus/mus_util.h
deleted file mode 100644
index 02d58a0f68c52e039297fdcdc24a363508648e27..0000000000000000000000000000000000000000
--- a/ui/aura/mus/mus_util.h
+++ /dev/null
@@ -1,24 +0,0 @@
-// Copyright 2015 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_AURA_MUS_MUS_UTIL_H_
-#define UI_AURA_MUS_MUS_UTIL_H_
-
-#include "ui/aura/aura_export.h"
-
-namespace ui {
-class Window;
-}
-
-namespace aura {
-
-class Window;
-
-AURA_EXPORT ui::Window* GetMusWindow(Window* window);
-
-AURA_EXPORT void SetMusWindow(Window* window, ui::Window* mus_window);
-
-}  // namespace aura
-
-#endif  // UI_AURA_MUS_MUS_UTIL_H_