signin: pull basic SigninManager functionality into new SigninManagerBase class.

chrome/browser/signin/signin_manager_factory.h

 // 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.
 
 #ifndef CHROME_BROWSER_SIGNIN_SIGNIN_MANAGER_FACTORY_H_
 #define CHROME_BROWSER_SIGNIN_SIGNIN_MANAGER_FACTORY_H_
 
 #include "base/memory/singleton.h"
 #include "chrome/browser/profiles/profile_keyed_service_factory.h"
 
 class SigninManager;
+class SigninManagerBase;
 class PrefRegistrySimple;
 class PrefRegistrySyncable;
 class Profile;
 
 // Singleton that owns all SigninManagers and associates them with
 // Profiles. Listens for the Profile's destruction notification and cleans up
 // the associated SigninManager.
 class SigninManagerFactory : public ProfileKeyedServiceFactory {
  public:
+
+#if defined(OS_CHROMEOS)
   // Returns the instance of SigninManager associated with this profile
   // (creating one if none exists). Returns NULL if this profile cannot have a
   // SigninManager (for example, if |profile| is incognito).
-  static SigninManager* GetForProfile(Profile* profile);
+  static SigninManagerBase* GetForProfile(Profile* profile);
 
   // Returns the instance of SigninManager associated with this profile. Returns
   // null if no SigninManager instance currently exists (will not create a new
   // instance).
+  static SigninManagerBase* GetForProfileIfExists(Profile* profile);
+#else
+  // On non-ChromeOS platforms, the SigninManager the factory creates will be
+  // an instance of the extended SigninManager class.
+  static SigninManager* GetForProfile(Profile* profile);
   static SigninManager* GetForProfileIfExists(Profile* profile);
+#endif
 
   // Returns an instance of the SigninManagerFactory singleton.
   static SigninManagerFactory* GetInstance();
 
   // Implementation of ProfileKeyedServiceFactory (public so tests can call it).
   virtual void RegisterUserPrefs(PrefRegistrySyncable* registry) OVERRIDE;
 
   // Registers the browser-global prefs used by SigninManager.
   static void RegisterPrefs(PrefRegistrySimple* registry);
 
  private:
   friend struct DefaultSingletonTraits<SigninManagerFactory>;
 
   SigninManagerFactory();
   virtual ~SigninManagerFactory();
 
   // ProfileKeyedServiceFactory:
   virtual ProfileKeyedService* BuildServiceInstanceFor(
       Profile* profile) const OVERRIDE;
 };
 
 #endif  // CHROME_BROWSER_SIGNIN_SIGNIN_MANAGER_FACTORY_H_