Cleanup the UseSharedProxies preference.

chrome/browser/net/proxy_service_factory.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_NET_PROXY_SERVICE_FACTORY_H_
 #define CHROME_BROWSER_NET_PROXY_SERVICE_FACTORY_H_
 
 #include "base/basictypes.h"
 
 class ChromeProxyConfigService;
 class CommandLine;
 class PrefProxyConfigTrackerImpl;
 class PrefService;
 
 #if defined(OS_CHROMEOS)
 namespace chromeos {
 class ProxyConfigServiceImpl;
 }
 #endif  // defined(OS_CHROMEOS)
 
+#if defined(OS_CHROMEOS)
+typedef chromeos::ProxyConfigServiceImpl PrefProxyConfigTracker;
+#else
+typedef PrefProxyConfigTrackerImpl PrefProxyConfigTracker;
+#endif  // defined(OS_CHROMEOS)
+
 namespace net {
 class NetLog;
 class NetworkDelegate;
 class ProxyConfigService;
 class ProxyService;
 class URLRequestContext;
 }  // namespace net
 
 class ProxyServiceFactory {
  public:
   // Creates a ProxyConfigService that delivers the system preferences
   // (or the respective ChromeOS equivalent).
   // The ChromeProxyConfigService returns "pending" until it has been informed
   // about the proxy configuration by calling its UpdateProxyConfig method.
   static ChromeProxyConfigService* CreateProxyConfigService();
 
-#if defined(OS_CHROMEOS)
-  static chromeos::ProxyConfigServiceImpl* CreatePrefProxyConfigTracker(
-      PrefService* pref_service);
-#else
-  static PrefProxyConfigTrackerImpl* CreatePrefProxyConfigTracker(
-      PrefService* pref_service);
-#endif  // defined(OS_CHROMEOS)
+  // Creates a PrefProxyConfigTracker that tracks preferences of a
+  // profile. On ChromeOS it additionaly tracks local state for shared proxy
+  // settings. This tracker should be used if the profile's preferences should
+  // be respected. On ChromeOS's signin screen this is for example not the case.
+  static PrefProxyConfigTracker* CreatePrefProxyConfigTrackerOfProfile(
+      PrefService* profile_prefs,
+      PrefService* local_state_prefs);
+
+  // Creates a PrefProxyConfigTracker that tracks local state only. This tracker
+  // should be used for the system request context and the signin screen
+  // (ChromeOS only).
+  static PrefProxyConfigTracker* CreatePrefProxyConfigTrackerOfLocalState(
+      PrefService* local_state_prefs);
 
   // Create a proxy service according to the options on command line.
   static net::ProxyService* CreateProxyService(
       net::NetLog* net_log,
       net::URLRequestContext* context,
       net::NetworkDelegate* network_delegate,
       net::ProxyConfigService* proxy_config_service,
       const CommandLine& command_line);
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(ProxyServiceFactory);
 };
 
 #endif  // CHROME_BROWSER_NET_PROXY_SERVICE_FACTORY_H_