Third Party authentication protocol.

remoting/protocol/authentication_method.cc

Index: remoting/protocol/authentication_method.cc
diff --git a/remoting/protocol/authentication_method.cc b/remoting/protocol/authentication_method.cc
index ab60f399535289f9e5084b7d646519a85e91fd1d..996390f8d1a2435199d0c2709261f17b81302bcf 100644
--- a/remoting/protocol/authentication_method.cc
+++ b/remoting/protocol/authentication_method.cc
@@ -19,7 +19,12 @@ AuthenticationMethod AuthenticationMethod::Invalid() {
 
 // static
 AuthenticationMethod AuthenticationMethod::Spake2(HashFunction hash_function) {
-  return AuthenticationMethod(hash_function);
+  return AuthenticationMethod(hash_function, false);
+}
+
+// static
+AuthenticationMethod AuthenticationMethod::ThirdParty() {
+  return AuthenticationMethod(NONE, true);
 }
 
 // static
@@ -29,6 +34,8 @@ AuthenticationMethod AuthenticationMethod::FromString(
     return Spake2(NONE);
   } else if (value == "spake2_hmac") {
     return Spake2(HMAC_SHA256);
+  } else if (value == "third_party") {
+    return ThirdParty();
   } else {
     return AuthenticationMethod::Invalid();
   }
@@ -65,11 +72,14 @@ std::string AuthenticationMethod::ApplyHashFunction(
 
 AuthenticationMethod::AuthenticationMethod()
     : invalid_(true),
+      requires_token_(false),
       hash_function_(NONE) {
 }
 
-AuthenticationMethod::AuthenticationMethod(HashFunction hash_function)
+AuthenticationMethod::AuthenticationMethod(HashFunction hash_function,
+                                           bool requires_token)
     : invalid_(false),
+      requires_token_(requires_token),
       hash_function_(hash_function) {
 }
 
@@ -81,15 +91,20 @@ AuthenticationMethod::HashFunction AuthenticationMethod::hash_function() const {
 const std::string AuthenticationMethod::ToString() const {
   DCHECK(is_valid());
 
+  if (requires_token_) {
+    return "third_party";
+  }
+
   switch (hash_function_) {
     case NONE:
       return "spake2_plain";
     case HMAC_SHA256:
       return "spake2_hmac";
+    default:
+      NOTREACHED();
   }
 
-  NOTREACHED();
-  return "";
+  return "invalid";
 }
 
 bool AuthenticationMethod::operator ==(
@@ -98,7 +113,7 @@ bool AuthenticationMethod::operator ==(
     return !other.is_valid();
   if (!other.is_valid())
     return false;
-  return hash_function_ == other.hash_function_;
+  return ToString() == other.ToString();
 }
 
 bool SharedSecretHash::Parse(const std::string& as_string) {