[Chromoting] Add a simple Windows app that registers and starts a host.

remoting/host/setup/host_starter.cc

Index: remoting/host/setup/host_starter.cc
diff --git a/remoting/host/setup/host_starter.cc b/remoting/host/setup/host_starter.cc
index 31847fe8eb069b7a70f15cce33e4f5bab139e197..1a1740138f597841dd7bbed027e0d1e2218da0e3 100644
--- a/remoting/host/setup/host_starter.cc
+++ b/remoting/host/setup/host_starter.cc
@@ -93,11 +93,11 @@ scoped_ptr<HostStarter> HostStarter::Create(
                       service_client.Pass(), daemon_controller.Pass()));
 }
 
-void HostStarter::StartHost(const std::string& host_name,
-                            const std::string& host_pin,
-                            bool consent_to_data_collection,
-                            const std::string& auth_code,
-                            CompletionCallback on_done) {
+void HostStarter::StartHost(
+    const std::string& host_name, const std::string& host_pin,
+    bool consent_to_data_collection, const std::string& auth_code,
+    CompletionCallback on_done,
+    scoped_refptr<base::SingleThreadTaskRunner> on_done_runner) {
   if (in_progress_) {
     on_done.Run(START_IN_PROGRESS);
     return;
@@ -107,6 +107,7 @@ void HostStarter::StartHost(const std::string& host_name,
   host_pin_ = host_pin;
   consent_to_data_collection_ = consent_to_data_collection;
   on_done_ = on_done;
+  on_done_runner_ = on_done_runner;
   // Map the authorization code to refresh and access tokens.
   oauth_client_->GetTokensFromAuthCode(oauth_client_info_, auth_code,
                                        kMaxGetTokensRetries, this);
@@ -148,8 +149,10 @@ void HostStarter::OnHostRegistered() {
 }
 
 void HostStarter::OnHostStarted(DaemonController::AsyncResult result) {
-  on_done_.Run(
-      (result == DaemonController::RESULT_OK) ? START_COMPLETE : START_ERROR);
+  Result done_result = START_ERROR;
+  if (result == DaemonController::RESULT_OK)
+    done_result = START_COMPLETE;
+  on_done_runner_->PostTask(FROM_HERE, base::Bind(on_done_, done_result));
   // TODO(simonmorris): Unregister the host if we didn't start it.
   in_progress_ = false;
 }