Remove usage of FOR_EACH_OBSERVER macro in ash/common

ash/common/system/chromeos/power/power_status.cc

Index: ash/common/system/chromeos/power/power_status.cc
diff --git a/ash/common/system/chromeos/power/power_status.cc b/ash/common/system/chromeos/power/power_status.cc
index 1966398738f1f3ebcb6d1493d913a984334c8785..f7356e149a75ccf04f1d847f7e42d841b4532045 100644
--- a/ash/common/system/chromeos/power/power_status.cc
+++ b/ash/common/system/chromeos/power/power_status.cc
@@ -511,7 +511,8 @@ void PowerStatus::PowerChanged(
     const power_manager::PowerSupplyProperties& proto) {
   proto_ = proto;
   SanitizeProto(&proto_);
-  FOR_EACH_OBSERVER(Observer, observers_, OnPowerStatusChanged());
+  for (auto& observer : observers_)
+    observer.OnPowerStatusChanged();
 }
 
 }  // namespace ash