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

chrome/browser/ui/global_error/global_error_service_unittest.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 "chrome/browser/ui/global_error/global_error_service.h"
 
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "chrome/browser/ui/global_error/global_error.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ skipping 56 matching lines @@
 int BaseError::count_ = 0;
 
 // A simple error that only has a menu item.
 class MenuError : public BaseError {
  public:
   explicit MenuError(int command_id, Severity severity)
       : command_id_(command_id),
         severity_(severity) {
   }
 
-  virtual Severity GetSeverity() { return severity_; }
+  virtual Severity GetSeverity() OVERRIDE { return severity_; }
 
   virtual bool HasMenuItem() OVERRIDE { return true; }
   virtual int MenuItemCommandID() OVERRIDE { return command_id_; }
   virtual string16 MenuItemLabel() OVERRIDE { return string16(); }
   virtual void ExecuteMenuItem(Browser* browser) OVERRIDE {}
 
  private:
   int command_id_;
   Severity severity_;
 
@@ skipping 79 matching lines @@
   service.AddGlobalError(error3);
   EXPECT_EQ(error3, service.GetHighestSeverityGlobalErrorWithWrenchMenuItem());
 
   // Remove the highest-severity error.
   service.RemoveGlobalError(error3);
   delete error3;
 
   // Now error2 should be the next highest severity error.
   EXPECT_EQ(error2, service.GetHighestSeverityGlobalErrorWithWrenchMenuItem());
 }