Fix crash when user disconnects It2Me host

remoting/signaling/delegating_signal_strategy.cc

 // Copyright 2013 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/signaling/delegating_signal_strategy.h"
 
 #include "base/bind.h"
 #include "base/rand_util.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "third_party/libjingle_xmpp/xmllite/xmlelement.h"
 #include "third_party/libjingle_xmpp/xmpp/constants.h"
 
 namespace remoting {
 
 DelegatingSignalStrategy::DelegatingSignalStrategy(
     std::string local_jid,
     scoped_refptr<base::SingleThreadTaskRunner> client_task_runner,
-    const SendIqCallback& send_iq_callback)
+    const IqCallback& send_iq_callback)
     : local_jid_(local_jid),
       delegate_task_runner_(base::ThreadTaskRunnerHandle::Get()),
       client_task_runner_(client_task_runner),
       send_iq_callback_(send_iq_callback),
-      weak_factory_(this) {}
+      weak_factory_(this) {
+  incoming_iq_callback_ =
+      base::BindRepeating(&OnIncomingMessageFromDelegate,
+                          weak_factory_.GetWeakPtr(), client_task_runner_);
+}
 
 DelegatingSignalStrategy::~DelegatingSignalStrategy() {}
 
-void DelegatingSignalStrategy::OnIncomingMessage(const std::string& message) {
-  if (!client_task_runner_->BelongsToCurrentThread()) {
-    client_task_runner_->PostTask(
-        FROM_HERE, base::Bind(&DelegatingSignalStrategy::OnIncomingMessage,
-                              weak_factory_.GetWeakPtr(), message));
+DelegatingSignalStrategy::IqCallback
+DelegatingSignalStrategy::GetIncomingMessageCallback() {
+  return incoming_iq_callback_;
+}
+
+// static
+void DelegatingSignalStrategy::OnIncomingMessageFromDelegate(
+    base::WeakPtr<DelegatingSignalStrategy> weak_ptr,
+    scoped_refptr<base::SingleThreadTaskRunner> client_task_runner,
+    const std::string& message) {
+  if (client_task_runner->BelongsToCurrentThread()) {
+    weak_ptr->OnIncomingMessage(message);
     return;
   }
 
+  client_task_runner->PostTask(
+      FROM_HERE, base::Bind(&DelegatingSignalStrategy::OnIncomingMessage,
+                            weak_ptr, message));
+}
+
+void DelegatingSignalStrategy::OnIncomingMessage(const std::string& message) {
+  DCHECK(client_task_runner_->BelongsToCurrentThread());
   std::unique_ptr<buzz::XmlElement> stanza(buzz::XmlElement::ForStr(message));
   if (!stanza.get()) {
     LOG(WARNING) << "Malformed XMPP stanza received: " << message;
     return;
   }
 
   for (auto& listener : listeners_) {
     if (listener.OnSignalStrategyIncomingStanza(stanza.get()))
       break;
   }
@@ skipping 41 matching lines @@
   delegate_task_runner_->PostTask(FROM_HERE,
                                   base::Bind(send_iq_callback_, stanza->Str()));
   return true;
 }
 
 std::string DelegatingSignalStrategy::GetNextId() {
   return base::Uint64ToString(base::RandUint64());
 }
 
 }  // namespace remoting