Add support for speaking SPDY to an HTTPS proxy....

net/http/http_proxy_client_socket.h

Index: net/http/http_proxy_client_socket.h
===================================================================
--- net/http/http_proxy_client_socket.h	(revision 58183)
+++ net/http/http_proxy_client_socket.h	(working copy)
@@ -39,7 +39,8 @@
                         const HostPortPair& endpoint,
                         const HostPortPair& proxy_server,
                         const scoped_refptr<HttpNetworkSession>& session,
-                        bool tunnel);
+                        bool tunnel,
+                        bool using_spdy);
 
   // On destruction Disconnect() is called.
   virtual ~HttpProxyClientSocket();
@@ -57,6 +58,10 @@
     return auth_;
   }
 
+  bool using_spdy() {
+    return using_spdy_;
+  }
+
   // ClientSocket methods:
 
   // Authenticates to the Http Proxy and then passes data freely.
@@ -140,6 +145,8 @@
   const HostPortPair endpoint_;
   scoped_refptr<HttpAuthController> auth_;
   const bool tunnel_;
+  // If true, then the connection to the proxy is a SPDY connection.
+  const bool using_spdy_;
 
   std::string request_headers_;