Do not use QUIC for requests that are through a proxy.

net/http/http_stream_factory_impl_job.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_stream_factory_impl_job.h"
 
 #include <algorithm>
 #include <string>
 
 #include "base/bind.h"
@@ skipping 650 matching lines @@
     // Remove unsupported proxies from the list.
     proxy_info_.RemoveProxiesWithoutScheme(
         ProxyServer::SCHEME_DIRECT | ProxyServer::SCHEME_QUIC |
         ProxyServer::SCHEME_HTTP | ProxyServer::SCHEME_HTTPS |
         ProxyServer::SCHEME_SOCKS4 | ProxyServer::SCHEME_SOCKS5);
 
     if (proxy_info_.is_empty()) {
       // No proxies/direct to choose from. This happens when we don't support
       // any of the proxies in the returned list.
       result = ERR_NO_SUPPORTED_PROXIES;
+    } else if (using_quic_ &&
+               (!proxy_info_.is_quic() && !proxy_info_.is_direct())) {
+      // QUIC can not be spoken to non-QUIC proxies.  This error should not be
+      // user visible, because the non-alternate job should be resumed.
+      result = ERR_NO_SUPPORTED_PROXIES;
     }
   }
 
   if (result != OK) {
     if (waiting_job_) {
       waiting_job_->Resume(this);
       waiting_job_ = NULL;
     }
     return result;
   }
@@ skipping 784 matching lines @@
       (net::LOAD_MAIN_FRAME | net::LOAD_SUB_FRAME | net::LOAD_PREFETCH |
        net::LOAD_IS_DOWNLOAD)) {
     // Avoid pipelining resources that may be streamed for a long time.
     return false;
   }
   return stream_factory_->http_pipelined_host_pool_.IsKeyEligibleForPipelining(
       *http_pipelining_key_.get());
 }
 
 }  // namespace net