Reduce usage of FOR_EACH_OBSERVER macro in base

base/process/port_provider_mac.cc

Index: base/process/port_provider_mac.cc
diff --git a/base/process/port_provider_mac.cc b/base/process/port_provider_mac.cc
index ac13949ac83bbabf039edb84d105c7b0e8af3c99..23d214c3f310a71fbee252a5681ba9ba579de2f5 100644
--- a/base/process/port_provider_mac.cc
+++ b/base/process/port_provider_mac.cc
@@ -21,7 +21,8 @@ void PortProvider::RemoveObserver(Observer* observer) {
 
 void PortProvider::NotifyObservers(ProcessHandle process) {
   base::AutoLock l(lock_);
-  FOR_EACH_OBSERVER(Observer, observer_list_, OnReceivedTaskPort(process));
+  for (auto& observer : observer_list_)
+    observer.OnReceivedTaskPort(process);
 }
 
 }  // namespace base