diff --git a/dev/tools/grunt/configs/less.js b/dev/tools/grunt/configs/less.js
index 9ae376b9e21ba..b1b87b6adc551 100644
--- a/dev/tools/grunt/configs/less.js
+++ b/dev/tools/grunt/configs/less.js
@@ -3,50 +3,49 @@
  * See COPYING.txt for license details.
  */
 
-'use strict';
+(function () {
+    'use strict';
+    var combo        = require('./combo'),
+        themes       = require('../tools/files-router').get('themes'),
+        _            = require('underscore'),
+        themeOptions = {},
+        lessOptions  = {
+            options: {
+                sourceMap: true,
+                strictImports: false,
+                sourceMapRootpath: '/',
+                sourceMapBasepath: function () {
+                    this.sourceMapURL = this.sourceMapFilename.substr(this.sourceMapFilename.lastIndexOf('/') + 1);
+                    return 'pub/';
+                },
+                dumpLineNumbers: false, // use 'comments' instead false to output line comments for source
+                ieCompat: false
+            },
+            setup: {
+                files: {
+                    '<%= path.css.setup %>/setup.css': '<%= path.less.setup %>/_setup.less'
+                }
+            },
+            updater: {
+                files: {
+                    '<%= path.css.updater %>/updater.css': '<%= path.less.setup %>/_setup.less'
+                }
+            },
+            documentation: {
+                files: {
+                    '<%= path.doc %>/docs.css': '<%= path.doc %>/source/docs.less'
+                }
+            }
+        };
 
-var combo  = require('./combo'),
-    themes = require('../tools/files-router').get('themes'),
-    _      = require('underscore');
+    _.each(themes, function (theme, name) {
+        themeOptions[name] = {
+            files: combo.lessFiles(name)
+        };
+    });
 
-var themeOptions = {};
-
-_.each(themes, function(theme, name) {
-    themeOptions[name] = {
-        files: combo.lessFiles(name)
-    };
-});
-
-var lessOptions = {
-    options: {
-        sourceMap: true,
-        strictImports: false,
-        sourceMapRootpath: '/',
-        sourceMapBasepath: function (f) {
-            this.sourceMapURL = this.sourceMapFilename.substr(this.sourceMapFilename.lastIndexOf('/') + 1);
-            return "/";
-        },
-        dumpLineNumbers: false, // use 'comments' instead false to output line comments for source
-        ieCompat: false
-    },
-    setup: {
-        files: {
-            '<%= path.css.setup %>/setup.css': '<%= path.less.setup %>/_setup.less'
-        }
-    },
-    updater: {
-        files: {
-            '<%= path.css.updater %>/updater.css': '<%= path.less.setup %>/_setup.less'
-        }
-    },
-    documentation: {
-        files: {
-            '<%= path.doc %>/docs.css': '<%= path.doc %>/source/docs.less'
-        }
-    }
-};
-
-/**
- * Compiles Less to CSS and generates necessary files if requested.
- */
-module.exports = _.extend(themeOptions, lessOptions);
+    /**
+     * Compiles Less to CSS and generates necessary files if requested.
+     */
+    module.exports = _.extend(themeOptions, lessOptions);
+})();