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

chrome/browser/ui/webui/memory_internals/memory_internals_proxy.cc

 // Copyright 2013 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/webui/memory_internals/memory_internals_proxy.h"
 
 #include <string>
 #include <vector>
 
 #include "base/bind.h"
@@ skipping 14 matching lines @@
 
 using content::BrowserThread;
 
 namespace {
 
 class BrowserProcessDetails : public MemoryDetails {
  public:
   typedef base::Callback<void(const ProcessData&)> DataCallback;
   explicit BrowserProcessDetails(const DataCallback& callback)
       : callback_(callback) {}
-  virtual void OnDetailsAvailable() {
+  virtual void OnDetailsAvailable() OVERRIDE {
     const std::vector<ProcessData>& browser_processes = processes();
     callback_.Run(browser_processes[0]);
   }
 
  private:
   virtual ~BrowserProcessDetails() {}
 
   DataCallback callback_;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserProcessDetails);
@@ skipping 60 matching lines @@
 
 void MemoryInternalsProxy::CallJavaScriptFunctionOnUIThread(
     const std::string& function, base::Value* args) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
   std::vector<const base::Value*> args_vector;
   args_vector.push_back(args);
   string16 update = content::WebUI::GetJavascriptCall(function, args_vector);
   UpdateUIOnUIThread(update);
 }