Require ECDHE cipher in remoting client.

remoting/protocol/ssl_hmac_channel_authenticator.cc

Index: remoting/protocol/ssl_hmac_channel_authenticator.cc
diff --git a/remoting/protocol/ssl_hmac_channel_authenticator.cc b/remoting/protocol/ssl_hmac_channel_authenticator.cc
index d047ec112428234733bfb100dc29a0191c90ad79..0a7c1d371145256f4a3c0f721027e60b3a0f1038 100644
--- a/remoting/protocol/ssl_hmac_channel_authenticator.cc
+++ b/remoting/protocol/ssl_hmac_channel_authenticator.cc
@@ -138,6 +138,7 @@ void SslHmacChannelAuthenticator::SecureAndAuthenticate(
     ssl_config.cert_io_enabled = false;
     ssl_config.rev_checking_enabled = false;
     ssl_config.allowed_bad_certs.push_back(cert_and_status);
+    ssl_config.require_ecdhe = true;
 
     net::HostPortPair host_and_port(kSslFakeHostName, 0);
     net::SSLClientSocketContext context;