Reduce usage of FOR_EACH_OBSERVER macro in components/

components/proxy_config/pref_proxy_config_tracker_impl_unittest.cc

Index: components/proxy_config/pref_proxy_config_tracker_impl_unittest.cc
diff --git a/components/proxy_config/pref_proxy_config_tracker_impl_unittest.cc b/components/proxy_config/pref_proxy_config_tracker_impl_unittest.cc
index 382f63460601671fd9751cf60902507656e71542..b0fd11edca0aaf4f717ee9c8fa8e6c735646dff0 100644
--- a/components/proxy_config/pref_proxy_config_tracker_impl_unittest.cc
+++ b/components/proxy_config/pref_proxy_config_tracker_impl_unittest.cc
@@ -40,8 +40,8 @@ class TestProxyConfigService : public net::ProxyConfigService {
                       ConfigAvailability availability) {
     config_ = config;
     availability_ = availability;
-    FOR_EACH_OBSERVER(net::ProxyConfigService::Observer, observers_,
-                      OnProxyConfigChanged(config, availability));
+    for (net::ProxyConfigService::Observer& observer : observers_)
+      observer.OnProxyConfigChanged(config, availability);
   }
 
  private: