Update CastSocket connection flow to check for receiver credentials.

chrome/browser/extensions/api/cast_channel/cast_message_util.cc

Index: chrome/browser/extensions/api/cast_channel/cast_message_util.cc
===================================================================
--- chrome/browser/extensions/api/cast_channel/cast_message_util.cc	(revision 230132)
+++ chrome/browser/extensions/api/cast_channel/cast_message_util.cc	(working copy)
@@ -11,6 +11,10 @@
 #include "chrome/browser/extensions/api/cast_channel/cast_channel.pb.h"
 #include "chrome/common/extensions/api/cast_channel.h"
 
+namespace {
+static const char kAuthNamespace[] = "com.google.cast.tp.deviceauth";
+}  // namespace
+
 namespace extensions {
 namespace api {
 namespace cast_channel {
@@ -83,7 +87,7 @@
   }
 }
 
-const std::string MessageProtoToString(const CastMessage& message_proto) {
+std::string MessageProtoToString(const CastMessage& message_proto) {
   std::string out("{");
   out += "namespace = " + message_proto.namespace_();
   out += ", sourceId = " + message_proto.source_id();
@@ -93,6 +97,30 @@
   return out;
 }
 
+std::string AuthMessageToString(const DeviceAuthMessage& message) {
+  std::string result;
+  if (message.SerializeToString(&result))
+    return result;
+  else
+    return "";
+}
+
+void CreateAuthChallengeMessage(CastMessage* message_proto) {
+  CHECK(message_proto);
+  DeviceAuthMessage auth_message;
+  auth_message.mutable_challenge();
+  std::string auth_message_string;
+  auth_message.SerializeToString(&auth_message_string);
+
+  message_proto->set_namespace_(kAuthNamespace);
+  message_proto->set_payload_type(CastMessage_PayloadType_BINARY);
+  message_proto->set_payload_binary(auth_message_string);
+}
+
+bool IsAuthMessage(const CastMessage& message) {
+  return message.namespace_() == kAuthNamespace;
+}
+
 }  // namespace cast_channel
 }  // namespace api
 }  // namespace extensions