Reduce FOR_EACH_OBSERVER usage in ui/

ui/native_theme/native_theme.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 "ui/native_theme/native_theme.h"
 
 #include <cstring>
 
 #include "ui/native_theme/native_theme_observer.h"
 
@@ skipping 17 matching lines @@
 
 void NativeTheme::AddObserver(NativeThemeObserver* observer) {
   native_theme_observers_.AddObserver(observer);
 }
 
 void NativeTheme::RemoveObserver(NativeThemeObserver* observer) {
   native_theme_observers_.RemoveObserver(observer);
 }
 
 void NativeTheme::NotifyObservers() {
-  FOR_EACH_OBSERVER(NativeThemeObserver, native_theme_observers_,
-                    OnNativeThemeUpdated(this));
+  for (NativeThemeObserver& observer : native_theme_observers_)
+    observer.OnNativeThemeUpdated(this);
 }
 
 NativeTheme::NativeTheme()
     : thumb_inactive_color_(0xeaeaea),
       thumb_active_color_(0xf4f4f4),
       track_color_(0xd3d3d3) {
 }
 
 NativeTheme::~NativeTheme() {}
 
 }  // namespace ui