Remove usage of FOR_EACH_OBSERVER macro in ios/

ios/public/provider/chrome/browser/signin/chrome_identity_service.mm

 // Copyright 2015 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/public/provider/chrome/browser/signin/chrome_identity_service.h"
 
 #include "ios/public/provider/chrome/browser/signin/chrome_identity_interaction_manager.h"
 
 namespace ios {
 
 ChromeIdentityService::ChromeIdentityService() {}
 
 ChromeIdentityService::~ChromeIdentityService() {
-  FOR_EACH_OBSERVER(Observer, observer_list_,
-                    OnChromeIdentityServiceWillBeDestroyed());
+  for (auto& observer : observer_list_)
+    observer.OnChromeIdentityServiceWillBeDestroyed();
 }
 
 void ChromeIdentityService::DismissDialogs() {}
 
 bool ChromeIdentityService::HandleApplicationOpenURL(UIApplication* application,
                                                      NSURL* url,
                                                      NSDictionary* options) {
   return false;
 }
 
@@ skipping 98 matching lines @@
 
 void ChromeIdentityService::RemoveObserver(Observer* observer) {
   observer_list_.RemoveObserver(observer);
 }
 
 bool ChromeIdentityService::IsInvalidGrantError(NSDictionary* user_info) {
   return false;
 }
 
 void ChromeIdentityService::FireIdentityListChanged() {
-  FOR_EACH_OBSERVER(Observer, observer_list_, OnIdentityListChanged());
+  for (auto& observer : observer_list_)
+    observer.OnIdentityListChanged();
 }
 
 void ChromeIdentityService::FireAccessTokenRefreshFailed(
     ChromeIdentity* identity,
     NSDictionary* user_info) {
-  FOR_EACH_OBSERVER(Observer, observer_list_,
-                    OnAccessTokenRefreshFailed(identity, user_info));
+  for (auto& observer : observer_list_)
+    observer.OnAccessTokenRefreshFailed(identity, user_info);
 }
 
 void ChromeIdentityService::FireProfileDidUpdate(ChromeIdentity* identity) {
-  FOR_EACH_OBSERVER(Observer, observer_list_, OnProfileUpdate(identity));
+  for (auto& observer : observer_list_)
+    observer.OnProfileUpdate(identity);
 }
 
 }  // namespace ios