filemanager: Files App change necessary to use "drive/root". It still works with "drive".

chrome/browser/resources/file_manager/js/path_util.js

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  * Type of a root directory.
  * @enum
  */
 var RootType = {
   DOWNLOADS: 'downloads',
   ARCHIVE: 'archive',
   REMOVABLE: 'removable',
   DRIVE: 'drive',
   DRIVE_OFFLINE: 'drive_offline'  // A fake root. Not the actual filesystem.
 };
 
 /**
  * Top directory for each root type.
  * @type {Object.<RootType,string>}
  */
 var RootDirectory = {
   DOWNLOADS: '/Downloads',
   ARCHIVE: '/archive',
   REMOVABLE: '/removable',
   DRIVE: '/drive',
   DRIVE_OFFLINE: '/drive_offline'  // A fake root. Not the actual filesystem.
 };
 
+/**
+ * Sub root directory for Drive. "root" and "other". This is not used now.
+ * TODO(haruki): Add namespaces support. http://crbug.com/174233.
+ * @enum
+ */
+var DriveSubRootDirectory = {
+  ROOT: 'root',
+  OTHER: 'other',
+};
+
 var PathUtil = {};
 
 /**
  * @param {string} path Path starting with '/'.
- * @return {string} Root directory (starting with '/').
+ * @return {string} Top directory (starting with '/').
  */
-PathUtil.getRootDirectory = function(path) {
+PathUtil.getTopDirectory = function(path) {
   var i = path.indexOf('/', 1);
-  return i === -1 ? path.substring(0) : path.substring(0, i);
+  return i === -1 ? path : path.substring(0, i);
 };
 
 /**
  * @param {string} path Any unix-style path (may start or not start from root).
  * @return {Array.<string>} Path components.
  */
 PathUtil.split = function(path) {
   var fromRoot = false;
   if (path[0] === '/') {
     fromRoot = true;
@@ skipping 37 matching lines @@
     path += components[i];
   }
   return path;
 };
 
 /**
  * @param {string} path Path starting with '/'.
  * @return {RootType} RootType.DOWNLOADS, RootType.DRIVE etc.
  */
 PathUtil.getRootType = function(path) {
-  var rootDir = PathUtil.getRootDirectory(path);
+  var rootDir = PathUtil.getTopDirectory(path);
   for (var type in RootDirectory) {
     if (rootDir === RootDirectory[type])
       return RootType[type];
   }
 };
 
 /**
  * @param {string} path Any path.
  * @return {string} The root path.
  */
 PathUtil.getRootPath = function(path) {
   var type = PathUtil.getRootType(path);
 
+  // TODO(haruki): Add support for "drive/root" and "drive/other".
   if (type == RootType.DOWNLOADS || type == RootType.DRIVE ||
       type == RootType.DRIVE_OFFLINE)
-    return PathUtil.getRootDirectory(path);
+    return PathUtil.getTopDirectory(path);
 
-  if (type == RootType.ARCHIVE || type == RootType.REMOVABLE) {
+  if (type == RootType.ARCHIVE ||
+      type == RootType.REMOVABLE) {
     var components = PathUtil.split(path);
     if (components.length > 1) {
       return PathUtil.join(components[0], components[1]);
     } else {
       return components[0];
     }
   }
 
   return '/';
 };
@@ skipping 41 matching lines @@
   if (path === RootDirectory.ARCHIVE)
     return str('ARCHIVE_DIRECTORY_LABEL');
   if (PathUtil.isParentPath(RootDirectory.ARCHIVE, path))
     return path.substring(RootDirectory.ARCHIVE.length + 1);
 
   if (path === RootDirectory.REMOVABLE)
     return str('REMOVABLE_DIRECTORY_LABEL');
   if (PathUtil.isParentPath(RootDirectory.REMOVABLE, path))
     return path.substring(RootDirectory.REMOVABLE.length + 1);
 
+  // TODO(haruki): Add support for "drive/root" and "drive/other".
   if (path === RootDirectory.DRIVE)
     return str('DRIVE_DIRECTORY_LABEL');
 
   if (path === RootDirectory.DRIVE_OFFLINE)
     return str('DRIVE_OFFLINE_COLLECTION_LABEL');
 
   return path;
 };