Cast: Let the extension control if DSCP is on or off.

chrome/common/extensions/api/cast_streaming_udp_transport.idl

Index: chrome/common/extensions/api/cast_streaming_udp_transport.idl
diff --git a/chrome/common/extensions/api/cast_streaming_udp_transport.idl b/chrome/common/extensions/api/cast_streaming_udp_transport.idl
index 11ca003db1c70876a39aed788344be49b804a55b..7532c6517fb6f055d5d965296acc28cbc9aa1e6e 100644
--- a/chrome/common/extensions/api/cast_streaming_udp_transport.idl
+++ b/chrome/common/extensions/api/cast_streaming_udp_transport.idl
@@ -26,5 +26,11 @@ namespace cast.streaming.udpTransport {
     // |destination| : The address and port to send packets to.
     [nocompile] static void setDestination(long transportId,
                                            IPEndPoint destination);
+
+    // Sets the options.
+    // Attributes of this object will be used to activate optional
+    // behaviours in the transport. Normally this is only used for
+    // experimentation. Must be called before setDestination.
+    [nocompile] static void setOptions(object options);
   };
 };