Add policy to restrict client domain for Me2Me.

remoting/protocol/it2me_host_authenticator_factory.h

Index: remoting/protocol/it2me_host_authenticator_factory.h
diff --git a/remoting/protocol/it2me_host_authenticator_factory.h b/remoting/protocol/it2me_host_authenticator_factory.h
index ee16c84fd7882aa64361613a384141a67a2fb3a3..fddea60e4cf2a221eb62a6ec2d71a661aedaeea9 100644
--- a/remoting/protocol/it2me_host_authenticator_factory.h
+++ b/remoting/protocol/it2me_host_authenticator_factory.h
@@ -26,7 +26,8 @@ class It2MeHostAuthenticatorFactory : public AuthenticatorFactory {
   It2MeHostAuthenticatorFactory(
       const std::string& local_cert,
       scoped_refptr<RsaKeyPair> key_pair,
-      const std::string& shared_secret);
+      const std::string& shared_secret,
+      const std::string& required_client_domain);
   ~It2MeHostAuthenticatorFactory() override;
 
   // AuthenticatorFactory interface.
@@ -39,6 +40,7 @@ class It2MeHostAuthenticatorFactory : public AuthenticatorFactory {
   std::string local_cert_;
   scoped_refptr<RsaKeyPair> key_pair_;
   std::string shared_secret_;
+  std::string required_client_domain_;
 
   DISALLOW_COPY_AND_ASSIGN(It2MeHostAuthenticatorFactory);
 };