Only mark a proxy as bad if we have confirmation that another proxy succeeded for the same request.

net/http/http_stream_factory_impl_job.cc

 // Copyright (c) 2011 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 "base/logging.h"
 #include "base/stl_util.h"
 #include "base/string_util.h"
 #include "base/stringprintf.h"
@@ skipping 818 matching lines @@
 
   bool use_relative_url = direct || request_info_.url.SchemeIs("https");
   stream_.reset(new SpdyHttpStream(spdy_session, use_relative_url));
   return OK;
 }
 
 int HttpStreamFactoryImpl::Job::DoCreateStreamComplete(int result) {
   if (result < 0)
     return result;
 
+  session_->proxy_service()->ReportSuccess(proxy_info_);
   next_state_ = STATE_NONE;
   return OK;
 }
 
 int HttpStreamFactoryImpl::Job::DoRestartTunnelAuth() {
   next_state_ = STATE_RESTART_TUNNEL_AUTH_COMPLETE;
   HttpProxyClientSocket* http_proxy_socket =
       static_cast<HttpProxyClientSocket*>(connection_->socket());
   return http_proxy_socket->RestartWithAuth(&io_callback_);
 }
@@ skipping 267 matching lines @@
                << (using_spdy ? "true\n" : "false\n");
   }
 }
 
 #if defined(OS_WIN)
 #pragma optimize( "", on )
 #pragma warning (default: 4748)
 #endif
 
 }  // namespace net