Remove usage of FOR_EACH_OBSERVER macro in ash/

ash/wm/video_detector.cc

 // Copyright (c) 2012 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 "ash/wm/video_detector.h"
 
 #include "ash/common/shell_window_ids.h"
 #include "ash/common/wm/window_state.h"
 #include "ash/common/wm_shell.h"
 #include "ash/common/wm_window.h"
@@ skipping 173 matching lines @@
 
 void VideoDetector::UpdateState() {
   State new_state = State::NOT_PLAYING;
   if (video_is_playing_) {
     new_state = fullscreen_root_windows_.empty() ? State::PLAYING_WINDOWED
                                                  : State::PLAYING_FULLSCREEN;
   }
 
   if (state_ != new_state) {
     state_ = new_state;
-    FOR_EACH_OBSERVER(Observer, observers_, OnVideoStateChanged(state_));
+    for (auto& observer : observers_)
+      observer.OnVideoStateChanged(state_);
   }
 }
 
 }  // namespace ash