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

remoting/signaling/fake_signal_strategy.cc

Index: remoting/signaling/fake_signal_strategy.cc
diff --git a/remoting/signaling/fake_signal_strategy.cc b/remoting/signaling/fake_signal_strategy.cc
index 12cd2c12ffdd78aca62cadee1bc5d760894983d5..cbe0451d08f4a79e950e5d595a55961a8a62662e 100644
--- a/remoting/signaling/fake_signal_strategy.cc
+++ b/remoting/signaling/fake_signal_strategy.cc
@@ -63,6 +63,11 @@ void FakeSignalStrategy::SetLocalJid(const std::string& jid) {
   jid_ = jid;
 }
 
+void FakeSignalStrategy::SimulatePackgeReordering() {
+  DCHECK(CalledOnValidThread());
+  simulate_reorder_ = true;
+}
+
 void FakeSignalStrategy::Connect() {
   DCHECK(CalledOnValidThread());
   FOR_EACH_OBSERVER(Listener, listeners_,
@@ -135,6 +140,42 @@ void FakeSignalStrategy::OnIncomingMessage(
     std::unique_ptr<buzz::XmlElement> stanza) {
   DCHECK(CalledOnValidThread());
 
+  if (!simulate_reorder_) {
+    NotifyListeners(std::move(stanza));
+    return;
+  }
+
+  // Simulate IQ message re-ordering by swapping the delivery order of the 2nd
+  // session-info message and the first transport-info message.
+  const buzz::XmlElement* jingle =
+      stanza->FirstNamed(buzz::QName("urn:xmpp:jingle:1", "jingle"));
+  std::string action = jingle->Attr(buzz::QName("", "action"));
+
+  if (action != "session-info" && action != "transport-info") {

[Sergey Ulanov, 2016/10/19 21:23:39]

I don't think we really need this logic here. The test could work as follows:
 1. Initialize connection.
 2. Call SimulatePackgeReordering().
 3. Send a set of transport messages and verify that they are received in
correct order.

[kelvinp, 2016/10/21 00:26:03]

Done.

+    NotifyListeners(std::move(stanza));
+    return;
+  }
+
+  if (action == "session-info") {
+    session_info_counts_++;
+    // Only reorder the 2nd session-info message.
+    if (session_info_counts_ == 2) {
+      pending_session_info_ = std::move(stanza);
+    } else {
+      NotifyListeners(std::move(stanza));
+    }
+  } else if (action == "transport-info" && session_info_counts_ == 2) {
+    NotifyListeners(std::move(stanza));
+    NotifyListeners(std::move(pending_session_info_));
+    pending_session_info_.reset();
+    simulate_reorder_ = false;
+  }
+}
+
+void FakeSignalStrategy::NotifyListeners(
+    std::unique_ptr<buzz::XmlElement> stanza) {
+  DCHECK(CalledOnValidThread());
+
   buzz::XmlElement* stanza_ptr = stanza.get();
   received_messages_.push_back(stanza.release());