signin: pull basic SigninManager functionality into new SigninManagerBase class.

chrome/browser/ui/webui/options/browser_options_handler.cc

Index: chrome/browser/ui/webui/options/browser_options_handler.cc
diff --git a/chrome/browser/ui/webui/options/browser_options_handler.cc b/chrome/browser/ui/webui/options/browser_options_handler.cc
index e0e0c8e0e41f8a5de4e3dd9c038ecf93490587eb..29f249c4b474a2d1fca6448e8c2a4dbac24b06c2 100644
--- a/chrome/browser/ui/webui/options/browser_options_handler.cc
+++ b/chrome/browser/ui/webui/options/browser_options_handler.cc
@@ -1171,12 +1171,17 @@ scoped_ptr<DictionaryValue> BrowserOptionsHandler::GetSyncStateDictionary() {
     return sync_status.Pass();
   }
 
+  bool signout_prohibited = false;
+#if !defined(OS_CHROMEOS)
   // Signout is not allowed if the user has policy (crbug.com/172204).
-  SigninManager* signin = SigninManagerFactory::GetForProfile(profile);
-  DCHECK(signin);
-  sync_status->SetBoolean("signoutAllowed", !signin->IsSignoutProhibited());
+  signout_prohibited =
+      SigninManagerFactory::GetForProfile(profile)->IsSignoutProhibited();
+#endif
+
   ProfileSyncService* service(
       ProfileSyncServiceFactory::GetInstance()->GetForProfile(profile));
+  SigninManagerBase* signin = service->signin();
+  sync_status->SetBoolean("signoutAllowed", !signout_prohibited);
   sync_status->SetBoolean("signinAllowed", signin->IsSigninAllowed());
   sync_status->SetBoolean("syncSystemEnabled", !!service);
   sync_status->SetBoolean("setupCompleted",