Turn on verbose flag for compiling file_manager.

ui/file_manager/file_manager/foreground/js/navigation_list_model.js

Index: ui/file_manager/file_manager/foreground/js/navigation_list_model.js
diff --git a/ui/file_manager/file_manager/foreground/js/navigation_list_model.js b/ui/file_manager/file_manager/foreground/js/navigation_list_model.js
index a817289675397e7d046cd652602d7ce026a9a2b6..af85f01aa6c77c71e9e43b68cfba9489fdf5095e 100644
--- a/ui/file_manager/file_manager/foreground/js/navigation_list_model.js
+++ b/ui/file_manager/file_manager/foreground/js/navigation_list_model.js
@@ -288,7 +288,7 @@ NavigationListModel.prototype = {
 /**
  * Returns the item at the given index.
  * @param {number} index The index of the entry to get.
- * @return {NavigationModelItem} The item at the given index.
+ * @return {NavigationModelItem|undefined} The item at the given index.
  */
 NavigationListModel.prototype.item = function(index) {
   if (index < this.volumeList_.length)
@@ -297,6 +297,7 @@ NavigationListModel.prototype.item = function(index) {
     return this.shortcutList_[index - this.volumeList_.length];
   if (index === this.length_() - 1)
     return this.menuModel_;
+  return undefined;
 };
 
 /**