Remove FOR_EACH_OBSERVER macro usage in chrome/browser/android

chrome/browser/android/data_usage/data_use_tab_model.cc

Index: chrome/browser/android/data_usage/data_use_tab_model.cc
diff --git a/chrome/browser/android/data_usage/data_use_tab_model.cc b/chrome/browser/android/data_usage/data_use_tab_model.cc
index 3a67b5d94c8df78dc2b459e0d510c93784e98e3b..b3b1c116a4e109c169ba0b94797e4ea694783849 100644
--- a/chrome/browser/android/data_usage/data_use_tab_model.cc
+++ b/chrome/browser/android/data_usage/data_use_tab_model.cc
@@ -327,20 +327,21 @@ bool DataUseTabModel::IsCustomTabPackageMatch(SessionID::id_type tab_id) const {
 void DataUseTabModel::NotifyObserversOfTrackingStarting(
     SessionID::id_type tab_id) {
   DCHECK(thread_checker_.CalledOnValidThread());
-  FOR_EACH_OBSERVER(TabDataUseObserver, observers_,
-                    NotifyTrackingStarting(tab_id));
+  for (auto& observer : observers_)
+    observer.NotifyTrackingStarting(tab_id);
 }
 
 void DataUseTabModel::NotifyObserversOfTrackingEnding(
     SessionID::id_type tab_id) {
   DCHECK(thread_checker_.CalledOnValidThread());
-  FOR_EACH_OBSERVER(TabDataUseObserver, observers_,
-                    NotifyTrackingEnding(tab_id));
+  for (auto& observer : observers_)
+    observer.NotifyTrackingEnding(tab_id);
 }
 
 void DataUseTabModel::NotifyObserversOfDataUseTabModelReady() {
   DCHECK(thread_checker_.CalledOnValidThread());
-  FOR_EACH_OBSERVER(TabDataUseObserver, observers_, OnDataUseTabModelReady());
+  for (auto& observer : observers_)
+    observer.OnDataUseTabModelReady();
 }
 
 void DataUseTabModel::GetCurrentAndNewLabelForNavigationEvent(