--- a/testing/specialpowers/content/specialpowersAPI.js
+++ b/testing/specialpowers/content/specialpowersAPI.js
@@ -2078,13 +2078,23 @@ SpecialPowersAPI.prototype = {
       },
     };
   },
 
   observeMutationEvents: function(mo, node, nativeAnonymousChildList, subtree) {
     unwrapIfWrapped(mo).observe(unwrapIfWrapped(node),
                                 {nativeAnonymousChildList, subtree});
   },
+
+  doCommand(window, cmd) {
+    return this._getDocShell(window).doCommand(cmd);
+  },
+
+  setCommandNode(window, node) {
+    return this._getDocShell(window).contentViewer
+               .QueryInterface(Ci.nsIContentViewerEdit)
+               .setCommandNode(node);
+  },
 };
 
 this.SpecialPowersAPI = SpecialPowersAPI;
 this.bindDOMWindowUtils = bindDOMWindowUtils;
 this.getRawComponents = getRawComponents;