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

ipc/ipc_test_sink.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ipc/ipc_test_sink.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include "build/build_config.h"
@@ skipping 27 matching lines @@
   NOTIMPLEMENTED();
   return base::ProcessId();
 }
 
 base::ProcessId TestSink::GetSelfPID() const {
   NOTIMPLEMENTED();
   return base::ProcessId();
 }
 
 bool TestSink::OnMessageReceived(const Message& msg) {
-  base::ObserverListBase<Listener>::Iterator it(&filter_list_);
-  Listener* observer;
-  while ((observer = it.GetNext()) != NULL) {
-    if (observer->OnMessageReceived(msg))
+  for (auto& observer : filter_list_) {
+    if (observer.OnMessageReceived(msg))
       return true;
   }
 
   // No filter handled the message, so store it.
   messages_.push_back(Message(msg));
   return true;
 }
 
 void TestSink::ClearMessages() {
   messages_.clear();
@@ skipping 43 matching lines @@
 }
 
 base::ScopedFD TestSink::TakeClientFileDescriptor() {
   NOTREACHED();
   return base::ScopedFD();
 }
 
 #endif  // defined(OS_POSIX) && !defined(OS_NACL)
 
 }  // namespace IPC