Don't rely on SSL cipher fallback in proxy auth.

net/http/http_proxy_client_socket.cc

 // Copyright (c) 2012 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.
 
 #include "net/http/http_proxy_client_socket.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/profiler/scoped_tracker.h"
 #include "base/strings/string_util.h"
@@ skipping 237 matching lines @@
 }
 
 int HttpProxyClientSocket::GetLocalAddress(IPEndPoint* address) const {
   return transport_->socket()->GetLocalAddress(address);
 }
 
 int HttpProxyClientSocket::PrepareForAuthRestart() {
   if (!response_.headers.get())
     return ERR_CONNECTION_RESET;
 
-  // If the connection can't be reused, just return ERR_CONNECTION_CLOSED.
-  // The request should be retried at a higher layer.
+  // If the connection can't be reused, return
+  // ERR_UNABLE_TO_REUSE_CONNECTION_FOR_PROXY_AUTH.  The request will be retried
+  // at a higher layer.
   if (!response_.headers->IsKeepAlive() ||
       !http_stream_parser_->CanFindEndOfResponse() ||
       !transport_->socket()->IsConnected()) {
     transport_->socket()->Disconnect();
     return ERR_UNABLE_TO_REUSE_CONNECTION_FOR_PROXY_AUTH;
   }
 
   // If the auth request had a body, need to drain it before reusing the socket.
   if (!http_stream_parser_->IsResponseBodyComplete()) {
     next_state_ = STATE_DRAIN_BODY;
@@ skipping 254 matching lines @@
     next_state_ = STATE_DRAIN_BODY;
     return OK;
   }
 
   return DidDrainBodyForAuthRestart();
 }
 
 //----------------------------------------------------------------
 
 }  // namespace net