Make proxy settings one atomic dictionary in the PrefStores such that modifications are atomic.

chrome/browser/extensions/extension_proxy_api.h

 // Copyright (c) 2010 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_EXTENSIONS_EXTENSION_PROXY_API_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_PROXY_API_H_
 
 #include <string>
 
 #include "chrome/browser/extensions/extension_function.h"
@@ skipping 24 matching lines @@
     };
     ProxyServer() : scheme("http"), host(""), port(INVALID_PORT) {}
 
     // The scheme of the proxy URI itself.
     std::string scheme;
     std::string host;
     int port;
   };
 
   bool GetProxyServer(const DictionaryValue* dict, ProxyServer* proxy_server);
-
-  bool ApplyMode(const std::string& mode, bool incognito);
-  bool ApplyPacScript(DictionaryValue* pac_dict, bool incognito);
-  bool ApplyProxyRules(DictionaryValue* proxy_rules, bool incognito);
+  bool GetProxyRules(DictionaryValue* proxy_rules, std::string* out);
 };
 
 class RemoveCustomProxySettingsFunction : public ProxySettingsFunction {
  public:
   virtual ~RemoveCustomProxySettingsFunction() {}
   virtual bool RunImpl();
 
   DECLARE_EXTENSION_FUNCTION_NAME(
       "experimental.proxy.removeCustomProxySettings")
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_PROXY_API_H_