Enable (optional) blocking of webrequests in case a PAC script cannot be fetched or is invalid.

net/proxy/proxy_service.h

 // 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.
 
 #ifndef NET_PROXY_PROXY_SERVICE_H_
 #define NET_PROXY_PROXY_SERVICE_H_
 #pragma once
 
 #include <vector>
 
@@ skipping 310 matching lines @@
   CompletionCallbackImpl<ProxyService> init_proxy_resolver_callback_;
 
   // Helper to download the PAC script (wpad + custom) and apply fallback rules.
   //
   // Note that the declaration is important here: |proxy_script_fetcher_| and
   // |proxy_resolver_| must outlive |init_proxy_resolver_|.
   scoped_ptr<InitProxyResolver> init_proxy_resolver_;
 
   State current_state_;
 
+  // Either OK or an ERR_* value indicating that a permanent error (e.g.
+  // failed to fetch the PAC script) prevents proxy resolution.
+  int permanent_error_;
+
   // This is the log where any events generated by |init_proxy_resolver_| are
   // sent to.
   NetLog* net_log_;
 
   // The earliest time at which we should run any proxy auto-config. (Used to
   // stall re-configuration following an IP address change).
   base::TimeTicks stall_proxy_autoconfig_until_;
 
   // The amount of time to stall requests following IP address changes.
   base::TimeDelta stall_proxy_auto_config_delay_;
@@ skipping 30 matching lines @@
 
   base::WaitableEvent event_;
   CompletionCallbackImpl<SyncProxyServiceHelper> callback_;
   ProxyInfo proxy_info_;
   int result_;
 };
 
 }  // namespace net
 
 #endif  // NET_PROXY_PROXY_SERVICE_H_