Part 2: 2301273 Fixed doc block and @file block in MenuActiveTrailTest.php
START PART 3: https://www.drupal.org/node/2301313
apply patch https://www.drupal.org/files/issues/menu-2256521-MenuLinkContentUI-review-do-not-test.patch
rename updateLink to updateDefinition
START PART 4: https://www.drupal.org/node/2301317
apply patch https://www.drupal.org/files/issues/menu-2256521-conversion-review-do-not-test.patch
and resolve 8.x conflicts
fix hook_uninstall to use the correct service
rename updateLink to updateDefinition
rename deleteLink to removeDefinition
rename isResetable() to isResettable()