Fix file manager to better handle missing roots and scan failure

chrome/browser/resources/file_manager/js/directory_model.js

Index: chrome/browser/resources/file_manager/js/directory_model.js
diff --git a/chrome/browser/resources/file_manager/js/directory_model.js b/chrome/browser/resources/file_manager/js/directory_model.js
index e846acc7d00927fbdb94c42b39779673e0ffaf09..9a081cfe209ecae07c167ce911e18b44e89790ea 100644
--- a/chrome/browser/resources/file_manager/js/directory_model.js
+++ b/chrome/browser/resources/file_manager/js/directory_model.js
@@ -328,9 +328,14 @@ DirectoryModel.prototype = {
   },
 
   /**
-   * Cancels waiting and scheduled rescans and starts new scan.
+   * Cancels waiting and scheduled rescans and starts new scan.  If the scan

[rginda, 2012/03/15 17:42:09]

I had been following python documentation guidelines, where comments start with
a single sentence, and the clarifying text in a new paragraph when necessary.

[Rick Byers, 2012/03/15 19:13:32]

Thanks, Done.  I agree that's better.

+   * completes successfully on the first attempt, the callback will be invoked
+   * and a 'scan-completed' event will be dispatched.  If the scan fails for
+   * any reason, we'll periodically retry until it succeeds (and then send a
+   * 'rescan-complete' event) or is cancelled or replaced by another scan.
    *
-   * @param {Function} callback Called when scan completed.
+   * @param {Function} callback Called if scan completes on the first attempt.
+   *   Note that this will NOT be called if the scan fails but later succeeds.
    */
   scan_: function(callback) {
     if (this.rescanTimeout_) {
@@ -497,9 +502,9 @@ DirectoryModel.prototype = {
    * changed.
    *
    * @param {DirectoryEntry} dirEntry The absolute path to the new directory.
-   * @param {function} action Action executed when the directory loaded.
-   *                              By default selects the first item
-   *                              (unless it's a save dialog).
+   * @param {function} action Action executed if the directory loads
+   *    successfully.  By default selects the first item (unless it's a save
+   *    dialog).
    * @param {boolean} initial True if it comes from setupPath and
    *                          false if caused by an user action.
    */
@@ -528,7 +533,9 @@ DirectoryModel.prototype = {
    *
    * @param {string} path The root path to use
    * @param {Function=} opt_loadedCallback Invoked when the entire directory
-   *     has been loaded and any default file selected.
+   *     has been loaded and any default file selected.  If there are any
+   *     errors loading the directory this will not get called (even if the
+   *     directory loads OK on retry later).
    * @param {Function=} opt_pathResolveCallback Invoked as soon as the path has
    *     been resolved, and called with the base and leaf portions of the path
    *     name, and a flag indicating if the entry exists.
@@ -597,7 +604,7 @@ DirectoryModel.prototype = {
       } else {
         // Well, we can't find the downloads dir. Let's just show something,
         // or we will get an infinite recursion.
-        this.changeDirectory('/', opt_loadedCallback, true);
+        this.changeDirectoryEntry_(this.root_, opt_loadedCallback, true);
       }
     }.bind(this);