Chromoting protocol layers to receive and send login messages

remoting/proto/auth.proto

Index: remoting/proto/auth.proto
diff --git a/remoting/proto/auth.proto b/remoting/proto/auth.proto
index 7b671e2a830ddb9b0d8bd88f8283872f48bad368..ddd44bbc581ef65d06014957ea37beb922616320 100644
--- a/remoting/proto/auth.proto
+++ b/remoting/proto/auth.proto
@@ -26,13 +26,13 @@ enum CredentialType {
 }
 
 message LocalLoginCredentials {
-  optional CredentialType type = 1;
+  required CredentialType type = 1;
   optional string username = 2;
   optional bytes credential = 3;
 }
 
 message LocalLoginStatus {
-  optional bool success = 1;
+  required bool success = 1;
 
   // Only populated if success is set to false.
   optional int32 tries_remaining = 2 [default = 0];
@@ -53,11 +53,11 @@ message LocalLoginProperties {
 // Sent from Client to Host.  This consists of both the login attempt,
 // and any session configuration information.
 message BeginSessionRequest {
-  optional LocalLoginCredentials credentials = 1;
+  required LocalLoginCredentials credentials = 1;
 }
 
 // Sent from Host to Client.  Replies with login success, and
 // final client configuration.
 message BeginSessionResponse {
-  optional LocalLoginStatus login_status = 1;
+  required LocalLoginStatus login_status = 1;
 }