Fix WebSocketServer extension parser.

net/websockets/websocket_extension.h

 // 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.
 
 #ifndef NET_WEBSOCKETS_WEBSOCKET_EXTENSION_H_
 #define NET_WEBSOCKETS_WEBSOCKET_EXTENSION_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 26 matching lines @@
   };
 
   WebSocketExtension();
   explicit WebSocketExtension(const std::string& name);
   ~WebSocketExtension();
 
   void Add(const Parameter& parameter) { parameters_.push_back(parameter); }
   const std::string& name() const { return name_; }
   const std::vector<Parameter>& parameters() const { return parameters_; }
   bool Equals(const WebSocketExtension& other) const;
+  std::string ToString() const;
 
   // The default copy constructor and the assignment operator are defined:
   // we need them.
  private:
   std::string name_;
   std::vector<Parameter> parameters_;
 };
 
 }  // namespace net
 
 #endif  // NET_WEBSOCKETS_WEBSOCKET_EXTENSION_H_