Replace FOR_EACH_OBSERVER in c/b/chromeos with range-based for

chrome/browser/chromeos/net/network_portal_detector_test_impl.cc

Index: chrome/browser/chromeos/net/network_portal_detector_test_impl.cc
diff --git a/chrome/browser/chromeos/net/network_portal_detector_test_impl.cc b/chrome/browser/chromeos/net/network_portal_detector_test_impl.cc
index 2c4e8bd838e81cf05f03418abd236197bfa1bb9a..cfaa5c558a40d839a9b0b5a5035bdb479c76b19f 100644
--- a/chrome/browser/chromeos/net/network_portal_detector_test_impl.cc
+++ b/chrome/browser/chromeos/net/network_portal_detector_test_impl.cc
@@ -39,8 +39,8 @@ void NetworkPortalDetectorTestImpl::NotifyObserversForTesting() {
   CaptivePortalState state;
   if (default_network_ && portal_state_map_.count(default_network_->guid()))
     state = portal_state_map_[default_network_->guid()];
-  FOR_EACH_OBSERVER(Observer, observers_,
-                    OnPortalDetectionCompleted(default_network_.get(), state));
+  for (auto& observer : observers_)
+    observer.OnPortalDetectionCompleted(default_network_.get(), state);
 }
 
 void NetworkPortalDetectorTestImpl::AddObserver(Observer* observer) {