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

net/http/http_net_log_params.h

 // Copyright (c) 2010 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 NET_HTTP_HTTP_NET_LOG_PARAMS_H_
 #define NET_HTTP_HTTP_NET_LOG_PARAMS_H_
 #pragma once
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/ref_counted.h"
 #include "net/base/net_log.h"
 #include "net/http/http_request_headers.h"
 
 class Value;
 
 namespace net {
 
 class HttpResponseHeaders;
 
 class NetLogHttpRequestParameter : public NetLog::EventParameters {
  public:
   NetLogHttpRequestParameter(const std::string& line,
                              const HttpRequestHeaders& headers);
 
-  Value* ToValue() const;
+  virtual Value* ToValue() const;
 
   const HttpRequestHeaders& GetHeaders() const {
     return headers_;
   }
 
   const std::string& GetLine() const {
     return line_;
   }
 
  private:
   virtual ~NetLogHttpRequestParameter();
 
   const std::string line_;
   HttpRequestHeaders headers_;
 
   DISALLOW_COPY_AND_ASSIGN(NetLogHttpRequestParameter);
 };
 
 class NetLogHttpResponseParameter : public NetLog::EventParameters {
  public:
   explicit NetLogHttpResponseParameter(
       const scoped_refptr<HttpResponseHeaders>& headers);
 
-  Value* ToValue() const;
+  virtual Value* ToValue() const;
 
   const HttpResponseHeaders& GetHeaders() const {
     return *headers_;
   }
 
  private:
   virtual ~NetLogHttpResponseParameter();
 
   const scoped_refptr<HttpResponseHeaders> headers_;
 
   DISALLOW_COPY_AND_ASSIGN(NetLogHttpResponseParameter);
 };
 
 }  // namespace net
 
 #endif  // NET_HTTP_HTTP_NET_LOG_PARAMS_H_