Remove usage of FOR_EACH_OBSERVER macro in ash/

ash/mus/keyboard_ui_mus.cc

 // 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.
 
 #include "ash/mus/keyboard_ui_mus.h"
 
 #include "ash/common/keyboard/keyboard_ui_observer.h"
 #include "base/memory/ptr_util.h"
 #include "services/shell/public/cpp/connector.h"
 
@@ skipping 29 matching lines @@
 }
 
 void KeyboardUIMus::OnKeyboardStateChanged(bool is_enabled,
                                            bool is_visible,
                                            uint64_t display_id,
                                            const gfx::Rect& bounds) {
   if (is_enabled_ == is_enabled)
     return;
 
   is_enabled_ = is_enabled;
-  FOR_EACH_OBSERVER(KeyboardUIObserver, *observers(),
-                    OnKeyboardEnabledStateChanged(is_enabled));
+  for (auto& observer : *observers())
+    observer.OnKeyboardEnabledStateChanged(is_enabled);
 }
 
 }  // namespace ash