Create a new preference which disables UDP protocol for WebRTC

chrome/common/pref_names.cc

Index: chrome/common/pref_names.cc
diff --git a/chrome/common/pref_names.cc b/chrome/common/pref_names.cc
index 9d21f958f0fa622a09711e80b9d3baea6b95d84c..5a99963bad8df23b14dee5f9752afa051abbd98a 100644
--- a/chrome/common/pref_names.cc
+++ b/chrome/common/pref_names.cc
@@ -1193,10 +1193,14 @@ const char kToolbarIconSurfacingBubbleLastShowTime[] =
     "toolbar_icon_surfacing_bubble_show_time";
 #endif
 
+#if defined(ENABLE_WEBRTC)
 // Whether WebRTC should bind to individual NICs to explore all possible routing
 // options. Default is true.
-#if defined(ENABLE_WEBRTC)
 const char kWebRTCMultipleRoutesEnabled[] = "webrtc.multiple_routes_enabled";
+// Whether WebRTC can use UDP to connect. When this is true, WebRTC will use UDP
+// transport which might leak IP addresses when a proxy is configured..  Default
+// is true.
+const char kWebRTCUdpTransportEnabled[] = "webrtc.udp_transport_enabled";
 #endif
 
 // *************** LOCAL STATE ***************