Use new callbacks in the IqRequest interface.

remoting/jingle_glue/javascript_iq_request.cc

Index: remoting/jingle_glue/javascript_iq_request.cc
diff --git a/remoting/jingle_glue/javascript_iq_request.cc b/remoting/jingle_glue/javascript_iq_request.cc
index ec83365e4ec0849148bc2ba630f5c63d079276a9..0b75c71a51244790a45ed78becd5d36efcb72c61 100644
--- a/remoting/jingle_glue/javascript_iq_request.cc
+++ b/remoting/jingle_glue/javascript_iq_request.cc
@@ -57,8 +57,9 @@ void JavascriptIqRegistry::OnIncomingStanza(const buzz::XmlElement* stanza) {
     // JavascriptIqRequest::SendIq(), but remove in
     // JavascriptIqRegistry::OnIq().  We should try to keep the
     // registration/deregistration in one spot.
-    if (it->second->callback_.get()) {
-      it->second->callback_->Run(stanza);
+    if (it->second->callback_.is_null()) {
+      it->second->callback_.Run(stanza);
+      it->second->callback_.Reset();
     } else {
       VLOG(1) << "No callback, so dropping: " << stanza->Str();
     }
@@ -90,8 +91,8 @@ void JavascriptIqRequest::SendIq(const std::string& type,
   signal_strategy_->SendStanza(MakeIqStanza(type, addressee, iq_body, id));
 }
 
-void JavascriptIqRequest::set_callback(ReplyCallback* callback) {
-  callback_.reset(callback);
+void JavascriptIqRequest::set_callback(const ReplyCallback& callback) {
+  callback_ = callback;
 }
 
 }  // namespace remoting