Replace ScopedThreadProxy with MessageLoopProxy & WeakPtrs.

remoting/host/host_user_interface.cc

Index: remoting/host/host_user_interface.cc
diff --git a/remoting/host/host_user_interface.cc b/remoting/host/host_user_interface.cc
index 365b52b6a2ae1eaea330771747c1a066f17f7430..0f52172cce7c5d17b32b12cd120a08dd2df76ff9 100644
--- a/remoting/host/host_user_interface.cc
+++ b/remoting/host/host_user_interface.cc
@@ -16,7 +16,8 @@ HostUserInterface::HostUserInterface(ChromotingHostContext* context)
     : host_(NULL),
       context_(context),
       is_monitoring_local_inputs_(false),
-      ui_thread_proxy_(context->ui_message_loop()),
+      ALLOW_THIS_IN_INITIALIZER_LIST(weak_factory_(this)),
+      weak_ptr_(weak_factory_.GetWeakPtr()),
       disable_disconnect_shortcut_on_mac_(false) {
 }
 
@@ -25,8 +26,6 @@ HostUserInterface::~HostUserInterface() {
 
   MonitorLocalInputs(false);
   ShowDisconnectWindow(false, std::string());
-
-  ui_thread_proxy_.Detach();
 }
 
 void HostUserInterface::Start(ChromotingHost* host,
@@ -47,19 +46,23 @@ void HostUserInterface::DisableDisconnectShortcutOnMac() {
 }
 
 void HostUserInterface::OnClientAuthenticated(const std::string& jid) {
+  DCHECK(network_message_loop()->BelongsToCurrentThread());
+
   authenticated_jid_ = jid;
 
   std::string username = jid.substr(0, jid.find('/'));
-  ui_thread_proxy_.PostTask(FROM_HERE, base::Bind(
+  ui_message_loop()->PostTask(FROM_HERE, base::Bind(
       &HostUserInterface::ProcessOnClientAuthenticated,
-      base::Unretained(this), username));
+      weak_ptr_, username));
 }
 
 void HostUserInterface::OnClientDisconnected(const std::string& jid) {
+  DCHECK(network_message_loop()->BelongsToCurrentThread());
+
   if (jid == authenticated_jid_) {
-    ui_thread_proxy_.PostTask(FROM_HERE, base::Bind(
+    ui_message_loop()->PostTask(FROM_HERE, base::Bind(
         &HostUserInterface::ProcessOnClientDisconnected,
-        base::Unretained(this)));
+        weak_ptr_));
   }
 }
 
@@ -67,20 +70,23 @@ void HostUserInterface::OnAccessDenied(const std::string& jid) {
 }
 
 void HostUserInterface::OnShutdown() {
+  DCHECK(network_message_loop()->BelongsToCurrentThread());
+
   // Host status observers must be removed on the network thread, so
   // it must happen here instead of in the destructor.
   host_->RemoveStatusObserver(this);
   host_ = NULL;
+
+  // TODO(wez): This isn't safe, since the callback gets called on UI thread.

[Sergey Ulanov, 2012/05/29 18:58:30]

I think we can just remove this line. The disconnection callback handler should
be able to handle the case when the host has been shut down already.

[Wez, 2012/05/30 00:18:39]

Done.  Not sure whether the intent was that Start() could be called to re-start
the interface.

   disconnect_callback_ = base::Closure();
 }
 
 void HostUserInterface::OnDisconnectCallback() {
   DCHECK(ui_message_loop()->BelongsToCurrentThread());
-  DCHECK(!disconnect_callback_.is_null());
 
   MonitorLocalInputs(false);
   ShowDisconnectWindow(false, std::string());
-  disconnect_callback_.Run();
+  DisconnectSession();

[Sergey Ulanov, 2012/05/29 18:58:30]

Do we need DisconnectSession() method at all?

[Wez, 2012/05/30 00:18:39]

It's used by It2MeHostUserInterface when the Disconnect button is pressed, or
the hot-key activated.

 }
 
 base::MessageLoopProxy* HostUserInterface::network_message_loop() const {
@@ -91,7 +97,10 @@ base::MessageLoopProxy* HostUserInterface::ui_message_loop() const {
 }
 
 void HostUserInterface::DisconnectSession() const {
-  return disconnect_callback_.Run();
+  DCHECK(ui_message_loop()->BelongsToCurrentThread());
+  DCHECK(!disconnect_callback_.is_null());
+
+  disconnect_callback_.Run();
 }
 
 void HostUserInterface::ProcessOnClientAuthenticated(
@@ -148,7 +157,7 @@ void HostUserInterface::ShowDisconnectWindow(bool show,
     disconnect_window_->Show(
         host_,
         base::Bind(&HostUserInterface::OnDisconnectCallback,
-                   base::Unretained(this)),
+                   weak_ptr_),
         username);
   } else {
     disconnect_window_->Hide();