fix: Avoid substitutions when Webpack was introduced

Avoid substitutions when Webpack was introduced

#4476 from w89612b/patch-1

Author: andrewnester

Diff for: lib/ace/worker/worker.js

@@ -153,10 +153,10 @@ window.define = function(id, deps, factory) {
     };
 };
 window.define.amd = {};
-require.tlns = {};
+window.require.tlns = {};
 window.initBaseUrls  = function initBaseUrls(topLevelNamespaces) {
     for (var i in topLevelNamespaces)
-        require.tlns[i] = topLevelNamespaces[i];
+        this.require.tlns[i] = topLevelNamespaces[i];
 };
 
 window.initSender = function initSender() {
@@ -210,8 +210,8 @@ window.onmessage = function(e) {
     else if (msg.init) {
         window.initBaseUrls(msg.tlns);
         sender = window.sender = window.initSender();
-        var clazz = require(msg.module)[msg.classname];
+        var clazz = this.require(msg.module)[msg.classname];
         main = window.main = new clazz(sender);
     }
 };
-})(this);
+})(this);