Process incoming IQs in the same order that they were sent.

remoting/signaling/fake_signal_strategy.h

Index: remoting/signaling/fake_signal_strategy.h
diff --git a/remoting/signaling/fake_signal_strategy.h b/remoting/signaling/fake_signal_strategy.h
index b828a2e2847559ba331a28b28b9bb42dc87fb82e..d18092c2848f516c4f2e00a6817b4d833195287f 100644
--- a/remoting/signaling/fake_signal_strategy.h
+++ b/remoting/signaling/fake_signal_strategy.h
@@ -45,6 +45,10 @@ class FakeSignalStrategy : public SignalStrategy,
 
   void SetLocalJid(const std::string& jid);
 
+  // Simulate IQ messages re-ordering by swapping the delivery order of
+  // next pair of messages.
+  void SimulatePackgeReordering();
+
   // SignalStrategy interface.
   void Connect() override;
   void Disconnect() override;
@@ -67,6 +71,7 @@ class FakeSignalStrategy : public SignalStrategy,
 
   // Called by the |peer_|. Takes ownership of |stanza|.
   void OnIncomingMessage(std::unique_ptr<buzz::XmlElement> stanza);
+  void NotifyListeners(std::unique_ptr<buzz::XmlElement> stanza);
   void SetPeerCallback(const PeerCallback& peer_callback);
 
   scoped_refptr<base::SingleThreadTaskRunner> main_thread_;
@@ -79,6 +84,9 @@ class FakeSignalStrategy : public SignalStrategy,
 
   base::TimeDelta send_delay_;
 
+  bool simulate_reorder_ = false;
+  std::unique_ptr<buzz::XmlElement> pending_stanza_;
+
   // All received messages, includes thouse still in |pending_messages_|.
   std::list<buzz::XmlElement*> received_messages_;