Bug #306866 --> context menu in message window shows to much options

some xpcnativewrapper fall out.

sr=bienvenu

mail/base/content/nsContextMenu.js

@@ -514,7 +514,7 @@ nsContextMenu.prototype = {
         // when there is one
         var reference = null;
         if (context == "selection")
-          reference = focusedWindow.__proto__.getSelection.call(focusedWindow);
+          reference = focusedWindow.getSelection();
         else if (context == "mathml")
           reference = this.target;
         else
@@ -745,7 +745,7 @@ nsContextMenu.prototype = {
     
     searchSelected : function() {
         var focusedWindow = document.commandDispatcher.focusedWindow;
-        var searchStr = focusedWindow.__proto__.getSelection.call(focusedWindow);
+        var searchStr = focusedWindow.getSelection();;
         searchStr = searchStr.toString();
         searchStr = searchStr.replace( /^\s+/, "" );
         searchStr = searchStr.replace(/(\n|\r|\t)+/g, " ");