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 dabe85ab9607fef23873a9725e9f27f6c6770917..ba4f66ead596505058ecf1ef1a12cbd306d22b76 100644
--- a/chrome/browser/ui/webui/options/browser_options_handler.cc
+++ b/chrome/browser/ui/webui/options/browser_options_handler.cc
@@ -1144,12 +1144,17 @@ scoped_ptr<DictionaryValue> BrowserOptionsHandler::GetSyncStateDictionary() {
     return sync_status.Pass();
   }
 
+  bool signout_prohibited = false;

[Andrew T Wilson (Slow), 2013/04/09 15:39:25]

Actually, I think signout should always be prohibited on cros (so, we should
default to true). I think the UI is already hidden on cros, but it doesn't hurt
to set the values correctly.

[tim (not reviewing), 2013/04/16 03:28:29]

If I understand correctly, the way it works now is "prohibit signout" is an
action only supported by the full-fledged desktop SigninManager, used by one of
the user policy services.  So there is no explicit restriction in the code w.r.t
signing out on cros.  

I'm happy to do that / look into moving SignOut out of SigninManagerBase if that
makes sense, but can I do it in a follow up?  It will require ifdefing or
splitting up more tests that try to test both platforms from each platform (e.g
ProfileSyncServiceStartupTest).

+#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",