Warn on missing OVERRIDE/virtual everywhere, not just in header files.

chrome/browser/notifications/notification_browsertest.cc

 // 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 <deque>
 #include <string>
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/compiler_specific.h"
@@ skipping 84 matching lines @@
     message_loop_runner_ = new content::MessageLoopRunner;
     message_loop_runner_->Run();
     return notification_received_;
   }
 
   // overridden from message_center::MessageCenterObserver:
   virtual void OnNotificationAdded(
       const std::string& notification_id) OVERRIDE {
     OnMessageCenterChanged();
   }
-  virtual void OnNotificationRemoved(
-      const std::string& notification_id, bool by_user) {
+  virtual void OnNotificationRemoved(const std::string& notification_id,
+                                     bool by_user) OVERRIDE {
     OnMessageCenterChanged();
   }
-  virtual void OnNotificationUpdated(const std::string& notification_id) {
+  virtual void OnNotificationUpdated(
+      const std::string& notification_id) OVERRIDE {
     OnMessageCenterChanged();
   }
 
   void OnMessageCenterChanged() {
     notification_received_ = true;
     if (message_loop_runner_)
       message_loop_runner_->Quit();
   }
 
   bool notification_received_;
@@ skipping 847 matching lines @@
   const std::deque<Balloon*>& balloons = GetActiveBalloons();
   ASSERT_EQ(1U, balloons.size());
   Balloon* balloon = balloons[0];
   const Notification& notification = balloon->notification();
   GURL EXPECTED_ICON_URL = test_server()->GetURL(kExpectedIconUrl);
   EXPECT_EQ(EXPECTED_ICON_URL, notification.icon_url());
   EXPECT_EQ(ASCIIToUTF16("Title2"), notification.title());
   EXPECT_EQ(ASCIIToUTF16("Body2"), notification.body());
 #endif
 }