Changes ScreenMusDelegate::GetWindowAtScreenPoint to return aura::Window

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() {}
 
+  ui::Window* GetUiWindowAtScreenPoint(const gfx::Point& point) {
+    return connection_->GetUiWindowAtScreenPoint(point);
+  }
+
   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_