Remove FOR_EACH_OBSERVER macro usage in chrome/browser/extensions

chrome/browser/extensions/api/identity/identity_api.cc

Index: chrome/browser/extensions/api/identity/identity_api.cc
diff --git a/chrome/browser/extensions/api/identity/identity_api.cc b/chrome/browser/extensions/api/identity/identity_api.cc
index e4c15c1f896fc14cbf2f5fb097a544ce7c5850c5..f76f95d3f3015a6d218732fea890d9b37e1a072c 100644
--- a/chrome/browser/extensions/api/identity/identity_api.cc
+++ b/chrome/browser/extensions/api/identity/identity_api.cc
@@ -225,7 +225,8 @@ std::string IdentityAPI::FindAccountKeyByGaiaId(const std::string& gaia_id) {
 }
 
 void IdentityAPI::Shutdown() {
-  FOR_EACH_OBSERVER(ShutdownObserver, shutdown_observer_list_, OnShutdown());
+  for (auto& observer : shutdown_observer_list_)
+    observer.OnShutdown();
   account_tracker_.RemoveObserver(this);
   account_tracker_.Shutdown();
 }