Receiving Connection: Proxy-Bypass induces proxy fallback.

net/http/http_network_transaction.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_network_transaction.h"
 
 #include <set>
 #include <vector>
 
 #include "base/bind.h"
@@ skipping 844 matching lines @@
 
   if (result == ERR_CONNECTION_CLOSED) {
     // For now, if we get at least some data, we do the best we can to make
     // sense of it and send it back up the stack.
     int rv = HandleConnectionClosedBeforeEndOfHeaders();
     if (rv != OK)
       return rv;
   }
   DCHECK(response_.headers);
 
+  // Server-induced fallback is supported only if this is a PAC configured
+  // proxy. See: http://crbug.com/143712
+  if (response_.was_fetched_via_proxy && proxy_info_.did_use_pac_script()) {
+    if (response_.headers != NULL &&
+        response_.headers->HasHeaderValue("connection", "proxy-bypass")) {
+      ProxyService* proxy_service = session_->proxy_service();
+      if (proxy_service->MarkProxyAsBad(proxy_info_, net_log_)) {
+        // Only retry in the case of GETs. We don't want to resubmit a POST
+        // if the proxy took some action.
+        if (request_->method == "GET") {
+          ResetConnectionAndRequestForResend();
+          return OK;
+        }
+      }
+    }
+  }
+
   // Like Net.HttpResponseCode, but only for MAIN_FRAME loads.
   if (request_->load_flags & LOAD_MAIN_FRAME) {
     const int response_code = response_.headers->response_code();
     UMA_HISTOGRAM_ENUMERATION(
         "Net.HttpResponseCode_Nxx_MainFrame", response_code/100, 10);
   }
 
   net_log_.AddEvent(
       NetLog::TYPE_HTTP_TRANSACTION_READ_RESPONSE_HEADERS,
       base::Bind(&HttpResponseHeaders::NetLogCallback, response_.headers));
@@ skipping 557 matching lines @@
       description = base::StringPrintf("Unknown state 0x%08X (%u)", state,
                                        state);
       break;
   }
   return description;
 }
 
 #undef STATE_CASE
 
 }  // namespace net