[iOS] Add accessor for ProfileOAuth2TokenServiceIOS instance and factory

ios/public/provider/chrome/browser/keyed_service_provider.cc

Index: ios/public/provider/chrome/browser/keyed_service_provider.cc
diff --git a/ios/public/provider/chrome/browser/keyed_service_provider.cc b/ios/public/provider/chrome/browser/keyed_service_provider.cc
index e5782af5b56ad77fa006d27d375ed8c9982cf4c5..09991f64da01be2fe2197173d5a9b6b452cbde28 100644
--- a/ios/public/provider/chrome/browser/keyed_service_provider.cc
+++ b/ios/public/provider/chrome/browser/keyed_service_provider.cc
@@ -25,6 +25,17 @@ KeyedServiceProvider::GetProfileOAuth2TokenServiceForBrowserState(
   return nullptr;
 }
 
+KeyedServiceBaseFactory*
+KeyedServiceProvider::GetProfileOAuth2TokenServiceIOSFactory() {
+  return nullptr;
+}
+
+ProfileOAuth2TokenServiceIOS*
+KeyedServiceProvider::GetProfileOAuth2TokenServiceIOSForBrowserState(
+    ChromeBrowserState* browser_state) {
+  return nullptr;
+}
+
 KeyedServiceBaseFactory* KeyedServiceProvider::GetSigninManagerFactory() {
   return nullptr;
 }