base: Stop passing a non-const ref to ObserverListBase::Iterator.

remoting/host/register_support_host_request_unittest.cc

 // Copyright (c) 2012 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 "remoting/host/register_support_host_request.h"
 
 #include "base/bind.h"
 #include "base/memory/ref_counted.h"
 #include "base/message_loop/message_loop.h"
 #include "base/observer_list.h"
@@ skipping 132 matching lines @@
   support_id->AddText(kSupportId);
   result->AddElement(support_id);
 
   XmlElement* support_id_lifetime = new XmlElement(
       QName(kChromotingXmlNamespace, "support-id-lifetime"));
   support_id_lifetime->AddText(kSupportIdLifetime);
   result->AddElement(support_id_lifetime);
 
   int consumed = 0;
   ObserverListBase<SignalStrategy::Listener>::Iterator it(
-      signal_strategy_listeners_);
+      &signal_strategy_listeners_);
   SignalStrategy::Listener* listener;
   while ((listener = it.GetNext()) != nullptr) {
     if (listener->OnSignalStrategyIncomingStanza(response.get()))
       consumed++;
   }
   EXPECT_EQ(1, consumed);
 
   base::RunLoop().RunUntilIdle();
 }
 
 }  // namespace remoting