Make ui::DisplayConfigurator a singleton

ui/display/chromeos/display_configurator.cc

 // Copyright 2014 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/display/chromeos/display_configurator.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/sys_info.h"
@@ skipping 995 matching lines @@
   if (success) {
     FOR_EACH_OBSERVER(
         Observer, observers_, OnDisplayModeChanged(cached_displays_));
   } else {
     FOR_EACH_OBSERVER(
         Observer, observers_, OnDisplayModeChangeFailed(cached_displays_,
                                                         attempted_state));
   }
 }
 
+// static
+DisplayConfigurator* DisplayConfigurator::GetInstance() {
+  return Singleton<DisplayConfigurator>::get();
+}
+
 }  // namespace ui