Revert of Removing HTTPS and SOCKS proxy server code.

webrtc/base/proxyserver.h

 /*
  *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 65 matching lines @@
 
  private:
   typedef std::list<ProxyBinding*> BindingList;
   SocketFactory* ext_factory_;
   SocketAddress ext_ip_;
   std::unique_ptr<AsyncSocket> server_socket_;
   BindingList bindings_;
   RTC_DISALLOW_COPY_AND_ASSIGN(ProxyServer);
 };
 
+// SocksProxyServer is a simple extension of ProxyServer to implement SOCKS.
+class SocksProxyServer : public ProxyServer {
+ public:
+  SocksProxyServer(SocketFactory* int_factory, const SocketAddress& int_addr,
+                   SocketFactory* ext_factory, const SocketAddress& ext_ip)
+      : ProxyServer(int_factory, int_addr, ext_factory, ext_ip) {
+  }
+ protected:
+  AsyncProxyServerSocket* WrapSocket(AsyncSocket* socket) override;
+  RTC_DISALLOW_COPY_AND_ASSIGN(SocksProxyServer);
+};
+
 }  // namespace rtc
 
 #endif  // WEBRTC_BASE_PROXYSERVER_H_