disableUntrustedNetwork skeleton

spec.bs

@@ -1516,6 +1516,7 @@ Several APIs specific to fenced frames are defined on the {{Fence}} interface.
       undefined reportEvent(optional ReportEventType event = {});
       undefined setReportEventDataForAutomaticBeacons(optional FenceEvent event = {});
       sequence<FencedFrameConfig> getNestedConfigs();
+      Promise<undefined> disableUntrustedNetwork();
   };
 </pre>
 
@@ -1699,6 +1700,19 @@ Several APIs specific to fenced frames are defined on the {{Fence}} interface.
   </wpt>
 </div>
 
+<div algorithm>
+  The <dfn method for=Fence>disableUntrustedNetwork()</dfn> method steps are:
+
+  1. Let |instance| be [=this=]'s [=relevant global object=]'s [=Window/browsing context=]'s
+     [=browsing context/fenced frame config instance=].
+
+  1. If |instance| is null, then return.
+
+  1. If the [=relevant settings object=]'s [=environment settings object/origin=] and |instance|'s
+     [=fenced frame config instance/mapped url=]'s [=url/origin=] are not [=same origin=], then
+     return.
+</div>
+
 <h3 id=new-request-destination>New [=request=] [=request/destination=]</h3>
 
 The processing model of a <{fencedframe}>'s navigation request deviates from that of the normal