Remove usage of base::ObserverList<T>::Iter::GetNext() in //remoting.

remoting/signaling/delegating_signal_strategy.cc

Index: remoting/signaling/delegating_signal_strategy.cc
diff --git a/remoting/signaling/delegating_signal_strategy.cc b/remoting/signaling/delegating_signal_strategy.cc
index e329a2047df589480932740d32bee2b02dbd8c9a..d1a374adf6f36fa86449a4b8ff748917200bd246 100644
--- a/remoting/signaling/delegating_signal_strategy.cc
+++ b/remoting/signaling/delegating_signal_strategy.cc
@@ -38,10 +38,8 @@ void DelegatingSignalStrategy::OnIncomingMessage(const std::string& message) {
     return;
   }
 
-  base::ObserverListBase<Listener>::Iterator it(&listeners_);
-  Listener* listener;
-  while ((listener = it.GetNext()) != nullptr) {
-    if (listener->OnSignalStrategyIncomingStanza(stanza.get()))
+  for (auto& listener : listeners_) {
+    if (listener.OnSignalStrategyIncomingStanza(stanza.get()))
       break;
   }
 }