Make sure auth error reporting handles guest mode correctly.

chrome/browser/profiles/profiles_state.cc

Index: chrome/browser/profiles/profiles_state.cc
diff --git a/chrome/browser/profiles/profiles_state.cc b/chrome/browser/profiles/profiles_state.cc
index 3fc99154509fe31abda972aa134fc1d73d552c9d..6b6fa7cae9ce2f4f6de3909933a116bb2be7c4d4 100644
--- a/chrome/browser/profiles/profiles_state.cc
+++ b/chrome/browser/profiles/profiles_state.cc
@@ -122,4 +122,10 @@ void UpdateGaiaProfilePhotoIfNeeded(Profile* profile) {
   GAIAInfoUpdateServiceFactory::GetInstance()->GetForProfile(profile)->Update();
 }
 
+SigninErrorController* GetSigninErrorController(Profile* profile) {
+  ProfileOAuth2TokenService* token_service =
+      ProfileOAuth2TokenServiceFactory::GetForProfile(profile);
+  return token_service ? token_service->signin_error_controller() : NULL;
+}
+
 }  // namespace profiles