Remove usage of FOR_EACH_OBSERVER macro in ios/

ios/chrome/browser/reading_list/reading_list_model.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 "ios/chrome/browser/reading_list/reading_list_model.h"
 
 ReadingListModel::ReadingListModel() : current_batch_updates_count_(0) {}
 ReadingListModel::~ReadingListModel() {}
 
 // Observer methods.
@@ skipping 14 matching lines @@
   return current_batch_updates_count_ > 0;
 }
 
 std::unique_ptr<ReadingListModel::ScopedReadingListBatchUpdate>
 ReadingListModel::BeginBatchUpdates() {
   std::unique_ptr<ReadingListModel::ScopedReadingListBatchUpdate> token(
       new ReadingListModel::ScopedReadingListBatchUpdate(this));
 
   ++current_batch_updates_count_;
   if (current_batch_updates_count_ == 1) {
-    FOR_EACH_OBSERVER(ReadingListModelObserver, observers_,
-                      ReadingListModelBeganBatchUpdates(this));
+    for (auto& observer : observers_)
+      observer.ReadingListModelBeganBatchUpdates(this);
   }
   return token;
 }
 
 void ReadingListModel::EndBatchUpdates() {
   DCHECK(IsPerformingBatchUpdates());
   --current_batch_updates_count_;
   if (current_batch_updates_count_ == 0) {
-    FOR_EACH_OBSERVER(ReadingListModelObserver, observers_,
-                      ReadingListModelCompletedBatchUpdates(this));
+    for (auto& observer : observers_)
+      observer.ReadingListModelCompletedBatchUpdates(this);
   }
 }