Made the ChromotingHost class not ref-counted.

remoting/host/plugin/host_script_object.cc

Index: remoting/host/plugin/host_script_object.cc
diff --git a/remoting/host/plugin/host_script_object.cc b/remoting/host/plugin/host_script_object.cc
index b091fe623eaff29cbba93d580b5ec6cbf1d22972..bb32964706c30f616c6f8957dadcc2ff509d03bf 100644
--- a/remoting/host/plugin/host_script_object.cc
+++ b/remoting/host/plugin/host_script_object.cc
@@ -142,8 +142,12 @@ class HostNPScriptObject::It2MeImpl
                            const std::string& support_id,
                            const base::TimeDelta& lifetime);
 
-  // Called when ChromotingHost::Shutdown() has completed.
-  void OnShutdownFinished();
+  // Shuts down |host_| on the network thread.

[Wez, 2013/04/02 19:58:33]

nit: ... and posts ShutdownOnUiThread() to shut down UI thread resources.

[alexeypa (please no reviews), 2013/04/08 23:28:17]

Done.

+  void ShutdownOnNetworkThread();
+
+  // Shuts down |desktop_environment_factory_| and |policy_watcher_| on
+  // the UI thread.
+  void ShutdownOnUiThread();
 
   // Called when initial policies are read, and when they change.
   void OnPolicyUpdate(scoped_ptr<base::DictionaryValue> policies);
@@ -168,7 +172,7 @@ class HostNPScriptObject::It2MeImpl
   scoped_ptr<DesktopEnvironmentFactory> desktop_environment_factory_;
   scoped_ptr<HostEventLogger> host_event_logger_;
 
-  scoped_refptr<ChromotingHost> host_;
+  scoped_ptr<ChromotingHost> host_;
   int failed_login_attempts_;
 
   scoped_ptr<policy_hack::PolicyWatcher> policy_watcher_;
@@ -254,13 +258,13 @@ void HostNPScriptObject::It2MeImpl::Disconnect() {
 
   switch (state_) {
     case kDisconnected:
-      OnShutdownFinished();
+      ShutdownOnUiThread();

[Wez, 2013/04/02 19:58:33]

nit: Call ShutdownOnNetworkThread() here and let that post on to
ShutdownOnUiThread(), so that the post-to-UI-thread can go in
ShutdownOnNetworkThread for clarity.

[alexeypa (please no reviews), 2013/04/08 23:28:17]

Done.

       return;
 
     case kStarting:
       SetState(kDisconnecting);
       SetState(kDisconnected);
-      OnShutdownFinished();
+      ShutdownOnUiThread();
       return;
 
     case kDisconnecting:
@@ -270,18 +274,17 @@ void HostNPScriptObject::It2MeImpl::Disconnect() {
       SetState(kDisconnecting);
 
       if (!host_) {
-        OnShutdownFinished();
+        SetState(kDisconnected);
+        ShutdownOnUiThread();
         return;
       }
 
       // ChromotingHost::Shutdown() may destroy SignalStrategy
       // synchronously, but SignalStrategy::Listener handlers are not
       // allowed to destroy SignalStrategy, so post task to call
-      // Shutdown() later.
+      // ChromotingHost::Shutdown() later.

[Wez, 2013/04/02 19:58:33]

nit: Move this comment into ShutdownOnNetworkThread, and do the
deferred-shutdown there, i.e. 

if (host_) {
  network->PostTask(Shutdown);
  network->DeleteSoon(host_.release());
}

[alexeypa (please no reviews), 2013/04/08 23:28:17]

It will not work because HostNPScriptObject::It2MeImpl should destroy
|signal_strategy_| only after the host has been shutdown. See
HostNPScriptObject::It2MeImpl::OnShutdown().

       host_context_->network_task_runner()->PostTask(
-          FROM_HERE, base::Bind(
-              &ChromotingHost::Shutdown, host_,
-              base::Bind(&It2MeImpl::OnShutdownFinished, this)));
+          FROM_HERE, base::Bind(&It2MeImpl::ShutdownOnNetworkThread, this));
       return;
   }
 }
@@ -369,7 +372,7 @@ void HostNPScriptObject::It2MeImpl::FinishConnect(
   }
 
   // Create the host.
-  host_ = new ChromotingHost(
+  host_.reset(new ChromotingHost(
       signal_strategy_.get(),
       desktop_environment_factory_.get(),
       CreateHostSessionManager(network_settings,
@@ -379,7 +382,7 @@ void HostNPScriptObject::It2MeImpl::FinishConnect(
       host_context_->video_capture_task_runner(),
       host_context_->video_encode_task_runner(),
       host_context_->network_task_runner(),
-      host_context_->ui_task_runner());
+      host_context_->ui_task_runner()));
   host_->AddStatusObserver(this);
   log_to_server_.reset(
       new LogToServer(host_->AsWeakPtr(), ServerLogEntry::IT2ME,
@@ -404,14 +407,25 @@ void HostNPScriptObject::It2MeImpl::FinishConnect(
   return;
 }
 
-void HostNPScriptObject::It2MeImpl::OnShutdownFinished() {
+void HostNPScriptObject::It2MeImpl::ShutdownOnNetworkThread() {
+  DCHECK(host_context_->network_task_runner()->BelongsToCurrentThread());
+  DCHECK_EQ(state_, kDisconnecting);
+
+  host_->Shutdown();
+  host_.reset();
+  SetState(kDisconnected);
+
+  ShutdownOnUiThread();
+}
+
+void HostNPScriptObject::It2MeImpl::ShutdownOnUiThread() {
   if (!host_context_->ui_task_runner()->BelongsToCurrentThread()) {

[Wez, 2013/04/02 19:58:33]

Rather than thread-hop here, can you move the post to ShutdownOnNetworkThread()?
 Shutdown should always be starting off from the network thread, so that
shouldn't add any extra thread-hop overhead.

[alexeypa (please no reviews), 2013/04/08 23:28:17]

Done.

     host_context_->ui_task_runner()->PostTask(
-        FROM_HERE, base::Bind(&It2MeImpl::OnShutdownFinished, this));
+        FROM_HERE, base::Bind(&It2MeImpl::ShutdownOnUiThread, this));
     return;
   }
 
-  // Note that OnShutdownFinished() may be called more than once.
+  // Note that ShutdownOnUiThread() may be called more than once.

[Wez, 2013/04/02 19:58:33]

Is this still true?

[alexeypa (please no reviews), 2013/04/08 23:28:17]

Done.

 
   // Destroy the DesktopEnvironmentFactory, to free thread references.
   desktop_environment_factory_.reset();
@@ -486,11 +500,6 @@ void HostNPScriptObject::It2MeImpl::OnShutdown() {
   signal_strategy_.reset();
   host_event_logger_.reset();
   host_->RemoveStatusObserver(this);
-  host_ = NULL;
-
-  if (state_ != kDisconnected) {
-    SetState(kDisconnected);
-  }
 }
 
 void HostNPScriptObject::It2MeImpl::OnPolicyUpdate(