Use Services.jsm module to obtain references to common services

Author: moisseev

chrome/received/content/scripts/messageHeader.js

@@ -2,11 +2,8 @@
 
 Received.Message = {};
 
-var prefs = Components.classes["@mozilla.org/preferences-service;1"]
-                .getService(Components.interfaces.nsIPrefBranch);
-
 Received.Message.displayReceivedHeader = function() {
-    var regexp = prefs.getCharPref("extensions.received.regexp");
+    var regexp = Services.prefs.getCharPref("extensions.received.regexp");
     var rowEl = document.getElementById("expandedReceivedRow");
     var hdrEl = document.getElementById("receivedReceivedHeader");
     var msg = gMessageDisplay.displayedMessage;

chrome/received/content/scripts/received.js

@@ -1,5 +1,7 @@
 "use strict";
 
+Components.utils.import("resource://gre/modules/Services.jsm");
+
 var Received = {};
 
 Received.parseReceivedHeader = function(headerStr, regexp) {