diff --git a/net/websockets/websocket_extension.h b/net/websockets/websocket_extension.h
new file mode 100644
index 0000000..5af4023
--- /dev/null
+++ b/net/websockets/websocket_extension.h
@@ -0,0 +1,57 @@
+// 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>
+
+#include "net/base/net_export.h"
+
+namespace net {
+
+// A WebSocketExtension instance represents a WebSocket extension specified
+// in RFC6455.
+class NET_EXPORT_PRIVATE WebSocketExtension {
+ public:
+  // Note that RFC6455 does not allow a parameter with an empty value.
+  class NET_EXPORT_PRIVATE Parameter {
+   public:
+    // Construct a parameter which does not have a value.
+    explicit Parameter(const std::string& name);
+    // Construct a parameter with a non-empty value.
+    Parameter(const std::string& name, const std::string& value);
+
+    bool HasValue() const { return !value_.empty(); }
+    const std::string& name() const { return name_; }
+    const std::string& value() const { return value_; }
+    bool Equals(const Parameter& other) const;
+
+    // The default copy constructor and the assignment operator are defined:
+    // we need them.
+   private:
+    std::string name_;
+    std::string value_;
+  };
+
+  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;
+
+  // 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_