Reduce FOR_EACH_OBSERVER usage in ui/

ui/base/user_activity/user_activity_detector.cc

Index: ui/base/user_activity/user_activity_detector.cc
diff --git a/ui/base/user_activity/user_activity_detector.cc b/ui/base/user_activity/user_activity_detector.cc
index 29dec4e8c988586f96b209df60e13877817ac4f4..bfda1cfdc91a96587501abf2cd021daaa48b3b24 100644
--- a/ui/base/user_activity/user_activity_detector.cc
+++ b/ui/base/user_activity/user_activity_detector.cc
@@ -123,7 +123,8 @@ void UserActivityDetector::HandleActivity(const ui::Event* event) {
       kNotifyIntervalMs) {
     if (VLOG_IS_ON(1))
       VLOG(1) << "Reporting user activity: " << GetEventDebugString(event);
-    FOR_EACH_OBSERVER(UserActivityObserver, observers_, OnUserActivity(event));
+    for (UserActivityObserver& observer : observers_)
+      observer.OnUserActivity(event);
     last_observer_notification_time_ = now;
   }
 }