mus: Use TooltipManagerAura in NativeWidgetMus.

ui/views/mus/test_utils.h

+// Copyright 2016 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_VIEWS_MUS_TEST_UTILS_H_
+#define UI_VIEWS_MUS_TEST_UTILS_H_
+
+#include "ui/views/mus/window_manager_connection.h"
+
+namespace views {
+namespace test {
+
+class WindowManagerConnectionTestApi {
+ public:
+  explicit WindowManagerConnectionTestApi(WindowManagerConnection* connection)
+      : connection_(connection) {}
+  ~WindowManagerConnectionTestApi() {}
+
+  ScreenMus* screen() { return connection_->screen_.get(); }
+
+ private:
+  WindowManagerConnection* connection_;
+
+  DISALLOW_COPY_AND_ASSIGN(WindowManagerConnectionTestApi);
+};
+
+}  // namespace test
+}  // namespace views
+
+#endif  // UI_VIEWS_MUS_TEST_UTILS_H_