Refactor out load_extensions_from_config function

IPython/html/static/base/js/utils.js

@@ -39,6 +39,20 define([
         );
     };
 
+    /**
+     * Wait for a config section to load, and then load the extensions specified
+     * in a 'load_extensions' key inside it.
+     */
+    function load_extensions_from_config(section) {
+        section.loaded.then(function() {
+            if (section.data.load_extensions) {
+                var nbextension_paths = Object.getOwnPropertyNames(
+                                            section.data.load_extensions);
+                IPython.load_extensions.apply(this, nbextension_paths);
+            }
+        });
+    }
+
     //============================================================================
     // Cross-browser RegEx Split
     //============================================================================
@@ -822,6 +836,7 define([
     };
     
     var utils = {
+        load_extensions_from_config: load_extensions_from_config,
         regex_split : regex_split,
         uuid : uuid,
         fixConsole : fixConsole,

IPython/html/static/notebook/js/main.js

@@ -150,13 +150,7 require([
     IPython.tooltip = notebook.tooltip;
 
     events.trigger('app_initialized.NotebookApp');
-    config_section.loaded.then(function() {
-        if (config_section.data.load_extensions) {
-            var nbextension_paths = Object.getOwnPropertyNames(
-                                        config_section.data.load_extensions);
-            IPython.load_extensions.apply(this, nbextension_paths);
-        }
-    });
+    utils.load_extensions_from_config(config_section);
     notebook.load_notebook(common_options.notebook_path);
 
 });