[Chromoting] Fix DCHECK when shutting down It2Me host from client side

remoting/host/it2me/it2me_host.cc

Index: remoting/host/it2me/it2me_host.cc
diff --git a/remoting/host/it2me/it2me_host.cc b/remoting/host/it2me/it2me_host.cc
index 0afaee6fc16d39d08523dec3c0784d66b83648a3..13e87d571892dfcedcd2fb23b895984e99da2618 100644
--- a/remoting/host/it2me/it2me_host.cc
+++ b/remoting/host/it2me/it2me_host.cc
@@ -96,12 +96,18 @@ void It2MeHost::Connect() {
 void It2MeHost::Disconnect() {
   DCHECK(task_runner_->BelongsToCurrentThread());
   host_context_->network_task_runner()->PostTask(
-      FROM_HERE, base::Bind(&It2MeHost::Shutdown, this));
+      FROM_HERE, base::Bind(&It2MeHost::DisconnectOnNetworkThread, this));
 }
 
-void It2MeHost::Shutdown() {
+void It2MeHost::DisconnectOnNetworkThread() {
   DCHECK(host_context_->network_task_runner()->BelongsToCurrentThread());
 
+  // Disconnect() may be called even when after the host been already stopped.
+  // Ignore repeated calls. See http://crbug.com/617474 for details.

[Sergey Ulanov, 2016/06/09 01:04:09]

I still think that the bug link is only a distraction here and is not useful.
Even if the purpose of this code is still not clear from the comment it can
always be traced to this CL and the bug.

+  if (state_ == kDisconnected) {
+    return;
+  }
+
   confirmation_dialog_proxy_.reset();
 
   host_event_logger_.reset();
@@ -164,7 +170,7 @@ void It2MeHost::OnConfirmationResult(It2MeConfirmationDialog::Result result) {
       break;
 
     case It2MeConfirmationDialog::Result::CANCEL:
-      Shutdown();
+      DisconnectOnNetworkThread();
       break;
 
     default:
@@ -284,7 +290,7 @@ void It2MeHost::OnAccessDenied(const std::string& jid) {
 
   ++failed_login_attempts_;
   if (failed_login_attempts_ == kMaxLoginAttempts) {
-    Shutdown();
+    DisconnectOnNetworkThread();
   }
 }
 
@@ -313,7 +319,7 @@ void It2MeHost::OnClientConnected(const std::string& jid) {
 void It2MeHost::OnClientDisconnected(const std::string& jid) {
   DCHECK(host_context_->network_task_runner()->BelongsToCurrentThread());
 
-  Shutdown();
+  DisconnectOnNetworkThread();
 }
 
 void It2MeHost::OnPolicyUpdate(
@@ -361,7 +367,7 @@ void It2MeHost::UpdateNatPolicy(bool nat_traversal_enabled) {
   // When transitioning from enabled to disabled, force disconnect any
   // existing session.
   if (nat_traversal_enabled_ && !nat_traversal_enabled && IsConnected()) {
-    Shutdown();
+    DisconnectOnNetworkThread();
   }
 
   nat_traversal_enabled_ = nat_traversal_enabled;
@@ -379,7 +385,7 @@ void It2MeHost::UpdateHostDomainPolicy(const std::string& host_domain) {
 
   // When setting a host domain policy, force disconnect any existing session.
   if (!host_domain.empty() && IsConnected()) {
-    Shutdown();
+    DisconnectOnNetworkThread();
   }
 
   required_host_domain_ = host_domain;
@@ -392,7 +398,7 @@ void It2MeHost::UpdateClientDomainPolicy(const std::string& client_domain) {
 
   // When setting a client  domain policy, disconnect any existing session.
   if (!client_domain.empty() && IsConnected()) {
-    Shutdown();
+    DisconnectOnNetworkThread();
   }
 
   required_client_domain_ = client_domain;
@@ -462,7 +468,7 @@ void It2MeHost::OnReceivedSupportID(
 
   if (!error_message.empty()) {
     SetState(kError, error_message);
-    Shutdown();
+    DisconnectOnNetworkThread();
     return;
   }
 
@@ -476,7 +482,7 @@ void It2MeHost::OnReceivedSupportID(
     std::string error_message = "Failed to generate host certificate.";
     LOG(ERROR) << error_message;
     SetState(kError, error_message);
-    Shutdown();
+    DisconnectOnNetworkThread();
     return;
   }