Problem/Motivation
If currentUser() is not going to be moved to \Drupal\Core\Plugin\PluginBase, remove the TODO in \Drupal\tracker\Plugin\Menu\UserTrackerTab.
Proposed resolution
Remove the TODO in \Drupal\tracker\Plugin\Menu\UserTrackerTab.
Remaining tasks
Patch
User interface changes
None
API changes
None
Data model changes
None
Release notes snippet
None