Add IsAuthenticated() method to SigninManager.

components/signin/core/browser/signin_manager_base.cc

 // Copyright 2014 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.
 
 #include "components/signin/core/browser/signin_manager_base.h"
 
 #include <string>
 #include <vector>
 
 #include "base/command_line.h"
@@ skipping 78 matching lines @@
   // Go ahead and update the last signed in username here as well. Once a
   // user is signed in the two preferences should match. Doing it here as
   // opposed to on signin allows us to catch the upgrade scenario.
   client_->GetPrefs()->SetString(prefs::kGoogleServicesLastUsername, username);
 }
 
 void SigninManagerBase::clear_authenticated_username() {
   authenticated_username_.clear();
 }
 
+bool SigninManagerBase::IsAuthenticated() const {
+  return !GetAuthenticatedAccountId().empty();
+}
+
 bool SigninManagerBase::AuthInProgress() const {
   // SigninManagerBase never kicks off auth processes itself.
   return false;
 }
 
 void SigninManagerBase::Shutdown() {}
 
 void SigninManagerBase::AddObserver(Observer* observer) {
   observer_list_.AddObserver(observer);
 }
@@ skipping 20 matching lines @@
                     NotifySigninValueChanged(field, value));
 }
 
 void SigninManagerBase::NotifyDiagnosticsObservers(
     const TimedSigninStatusField& field,
     const std::string& value) {
   FOR_EACH_OBSERVER(SigninDiagnosticsObserver,
                     signin_diagnostics_observers_,
                     NotifySigninValueChanged(field, value));
 }