Reduce FOR_EACH_OBSERVER usage in ui/

ui/native_theme/native_theme.cc

Index: ui/native_theme/native_theme.cc
diff --git a/ui/native_theme/native_theme.cc b/ui/native_theme/native_theme.cc
index e4911c97d01e7d68167409c9b96041240293faf7..966131853bd160120d4e072396943411ac3e45c7 100644
--- a/ui/native_theme/native_theme.cc
+++ b/ui/native_theme/native_theme.cc
@@ -35,8 +35,8 @@ void NativeTheme::RemoveObserver(NativeThemeObserver* observer) {
 }
 
 void NativeTheme::NotifyObservers() {
-  FOR_EACH_OBSERVER(NativeThemeObserver, native_theme_observers_,
-                    OnNativeThemeUpdated(this));
+  for (NativeThemeObserver& observer : native_theme_observers_)
+    observer.OnNativeThemeUpdated(this);
 }
 
 NativeTheme::NativeTheme()