mustash: Enable connections to mus from the Chrome renderer [take 2]

ui/aura/mus/mus_util.cc

Index: ui/aura/mus/mus_util.cc
diff --git a/ui/aura/mus/mus_util.cc b/ui/aura/mus/mus_util.cc
new file mode 100644
index 0000000000000000000000000000000000000000..ed57f6a6e1ad3bed64faab0b00d3149cb4a45698
--- /dev/null
+++ b/ui/aura/mus/mus_util.cc
@@ -0,0 +1,21 @@
+// 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.
+
+#include "ui/aura/mus/mus_util.h"
+
+#include "ui/aura/window.h"
+
+namespace aura {
+
+mus::Window* GetMusWindow(Window* window) {
+  if (!window)
+    return nullptr;
+  return static_cast<mus::Window*>(window->GetNativeWindowProperty("mus"));
+}
+
+void SetMusWindow(Window* window, mus::Window* mus_window) {
+  window->SetNativeWindowProperty("mus", mus_window);
+}
+
+}  // namespace aura