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

remoting/host/setup/host_starter.h

Index: remoting/host/setup/host_starter.h
diff --git a/remoting/host/setup/host_starter.h b/remoting/host/setup/host_starter.h
index 91db5c074a6465c60f85dbe1a0bcf460fcafbd85..a25f9d3478d48b68fe1980c7d1beb480f2172f96 100644
--- a/remoting/host/setup/host_starter.h
+++ b/remoting/host/setup/host_starter.h
@@ -44,7 +44,8 @@ class HostStarter :
   // from a browser. This method uses that code to get an OAuth2 refresh token.
   void StartHost(const std::string& host_name, const std::string& host_pin,
                  bool consent_to_data_collection, const std::string& auth_code,
-                 CompletionCallback on_done);
+                 CompletionCallback on_done,
+                 scoped_refptr<base::SingleThreadTaskRunner> on_done_runner);
 
   // gaia::GaiaOAuthClient::Delegate
   virtual void OnGetTokensResponse(const std::string& refresh_token,
@@ -79,6 +80,7 @@ class HostStarter :
   std::string host_pin_;
   bool consent_to_data_collection_;
   CompletionCallback on_done_;
+  scoped_refptr<base::SingleThreadTaskRunner> on_done_runner_;
   std::string refresh_token_;
   std::string access_token_;
   std::string user_email_;