Add the "virtual" keyword on method overrides that are missing it.

chrome/worker/nativewebworker_impl.h

 // Copyright (c) 2009 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.
 
 #ifndef CHROME_WORKER_NATIVEWEBWORKER_IMPL_H_
 #define CHROME_WORKER_NATIVEWEBWORKER_IMPL_H_
 #pragma once
 
 #include "base/basictypes.h"
 #include "third_party/WebKit/WebKit/chromium/public/WebWorker.h"
 #include "third_party/WebKit/WebKit/chromium/public/WebWorkerClient.h"
 
 
 // Forward declaration for the listener thread pointer.
 class NativeWebWorkerListenerThread;
 
 // This class is used by the worker process code to talk to the Native Client
 // worker implementation.
 class NativeWebWorkerImpl : public WebKit::WebWorker {
  public:
   explicit NativeWebWorkerImpl(WebKit::WebWorkerClient* client);
   virtual ~NativeWebWorkerImpl();
 
   static WebWorker* create(WebKit::WebWorkerClient* client);
 
   // WebWorker implementation.
-  void startWorkerContext(const WebKit::WebURL& script_url,
-                          const WebKit::WebString& user_agent,
-                          const WebKit::WebString& source_code);
-  void terminateWorkerContext();
-  void postMessageToWorkerContext(
+  virtual void startWorkerContext(const WebKit::WebURL& script_url,
+                                  const WebKit::WebString& user_agent,
+                                  const WebKit::WebString& source_code);
+  virtual void terminateWorkerContext();
+  virtual void postMessageToWorkerContext(
       const WebKit::WebString& message,
       const WebKit::WebMessagePortChannelArray& channels);
-  void workerObjectDestroyed();
-  void clientDestroyed();
+  virtual void workerObjectDestroyed();
+  virtual void clientDestroyed();
 
  private:
   WebKit::WebWorkerClient* client_;
   struct NaClApp* nap_;
   struct NaClSrpcChannel* channel_;
   NativeWebWorkerListenerThread* upcall_thread_;
   struct NaClDesc* descs_[2];
 
   DISALLOW_COPY_AND_ASSIGN(NativeWebWorkerImpl);
 };
 
 #endif  // CHROME_WORKER_NATIVEWEBWORKER_IMPL_H_