Remove usage of FOR_EACH_OBSERVER macro in blimp

blimp/engine/app/settings_manager.cc

Index: blimp/engine/app/settings_manager.cc
diff --git a/blimp/engine/app/settings_manager.cc b/blimp/engine/app/settings_manager.cc
index 0c7fd35b62156cfcff0a9827154264278670932d..50254fdbaff99d7dceb69938ea1fc48303fc8d19 100644
--- a/blimp/engine/app/settings_manager.cc
+++ b/blimp/engine/app/settings_manager.cc
@@ -43,7 +43,8 @@ void SettingsManager::UpdateEngineSettings(const EngineSettings& settings) {
 
   if (settings_.record_whole_document != old_settings.record_whole_document) {
     // Notify the observers that the web preferences have changed.
-    FOR_EACH_OBSERVER(Observer, observer_list_, OnWebPreferencesChanged());
+    for (auto& observer : observer_list_)
+      observer.OnWebPreferencesChanged();
   }
 }