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

chrome/browser/prefs/proxy_config_dictionary.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 CHROME_BROWSER_PREFS_PROXY_CONFIG_DICTIONARY_H_
 #define CHROME_BROWSER_PREFS_PROXY_CONFIG_DICTIONARY_H_
 #pragma once
 
 #include <string>
 
@@ skipping 13 matching lines @@
 // }
 // See proxy_config_dictionary.cc for the structure of the respective strings.
 class ProxyConfigDictionary {
  public:
   // Creates a deep copy of |dict| and leaves ownership to caller.
   explicit ProxyConfigDictionary(const DictionaryValue* dict);
   ~ProxyConfigDictionary();
 
   bool GetMode(ProxyPrefs::ProxyMode* out) const;
   bool GetPacUrl(std::string* out) const;
+  bool GetPacMandatory(bool* out) const;
   bool GetProxyServer(std::string* out) const;
   bool GetBypassList(std::string* out) const;
   bool HasBypassList() const;
 
   static DictionaryValue* CreateDirect();
   static DictionaryValue* CreateAutoDetect();
-  static DictionaryValue* CreatePacScript(const std::string& pac_url);
+  static DictionaryValue* CreatePacScript(const std::string& pac_url,
+                                          bool pac_mandatory);
   static DictionaryValue* CreateFixedServers(
       const std::string& proxy_server,
       const std::string& bypass_list);
   static DictionaryValue* CreateSystem();
  private:
   static DictionaryValue* CreateDictionary(ProxyPrefs::ProxyMode mode,
                                            const std::string& pac_url,
+                                           bool pac_mandatory,
                                            const std::string& proxy_server,
                                            const std::string& bypass_list);
 
   scoped_ptr<DictionaryValue> dict_;
 
   DISALLOW_COPY_AND_ASSIGN(ProxyConfigDictionary);
 };
 
 #endif  // CHROME_BROWSER_PREFS_PROXY_CONFIG_DICTIONARY_H_