Test if clang warns on valid code.

chrome/browser/notifications/notification_ui_manager_mac.mm

 // Copyright (c) 2012 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 "chrome/browser/notifications/notification_ui_manager_mac.h"
 
 #include "base/mac/cocoa_protocols.h"
 #include "base/mac/mac_util.h"
 #include "base/sys_string_conversions.h"
 #include "chrome/browser/notifications/notification.h"
@@ skipping 81 matching lines @@
     instance = impl = new NotificationUIManagerImpl(local_state);
   }
 
   impl->Initialize(balloons);
   balloons->set_space_change_listener(impl);
 
   return instance;
 }
 
 NotificationUIManagerMac::ControllerNotification::ControllerNotification(
-    id<CrUserNotification> a_view, Notification* a_model)
-    : view(a_view),
-      model(a_model) {
+    id<CrUserNotification> view, Notification* model)
+    : view(view),
+      model(model) {
 }
 
 NotificationUIManagerMac::ControllerNotification::~ControllerNotification() {
   [view release];
   delete model;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 
 NotificationUIManagerMac::NotificationUIManagerMac(PrefService* local_state)
@@ skipping 183 matching lines @@
     notification->Click();
 }
 
 - (BOOL)userNotificationCenter:(NSUserNotificationCenter*)center
      shouldPresentNotification:(id<CrUserNotification>)nsNotification {
   // Always display notifications, regardless of whether the app is foreground.
   return YES;
 }
 
 @end