Add the code to delete the unused folder-shortcut data

The data in chrome.storage.local had been used but is now no longer used. This patch adds the code to remove them, in order to save the limited user storage.

BUG=268784
TEST=Files.app launches without error in console.
R=mtomasz@chromium.org

Review URL: https://codereview.chromium.org/22361002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@215856 0039d316-1c4b-4281-b951-d872f2087c98

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

@@ -246,6 +246,10 @@ var BOTTOM_MARGIN_FOR_PREVIEW_PANEL_PX = 52;
       }.bind(this));
     }.bind(this));
 
+    // Removes the user data which is no longer used.
+    // TODO(yoshiki): Remove this in M31 http://crbug.com/268784/
+    chrome.storage.local.remove('folder-shortcuts-list');
+
     group.run(callback);
   };