Remove usage of FOR_EACH_OBSERVER macro in ash/

ash/first_run/first_run_helper_impl.cc

Index: ash/first_run/first_run_helper_impl.cc
diff --git a/ash/first_run/first_run_helper_impl.cc b/ash/first_run/first_run_helper_impl.cc
index e472ab5424ce9eb0580b3a6a290e72fa9703b828..25a6bee6cf50ffb123d9f9f57c20224cb47dde4d 100644
--- a/ash/first_run/first_run_helper_impl.cc
+++ b/ash/first_run/first_run_helper_impl.cc
@@ -62,7 +62,8 @@ gfx::Rect FirstRunHelperImpl::GetAppListButtonBounds() {
 }
 
 void FirstRunHelperImpl::Cancel() {
-  FOR_EACH_OBSERVER(Observer, observers(), OnCancelled());
+  for (auto& observer : observers())
+    observer.OnCancelled();
 }
 
 bool FirstRunHelperImpl::IsCancelingKeyEvent(ui::KeyEvent* event) {