Convert legacy Polymer elements to class-based
Convert legacy Polymer elements to class-based

Change-Id: Iff3085b63289f3d86aa8998c08583e4e934dbe36

GerritCodeReview/plugins_delete-project,GerritCodeReview/plugins_delete-project,GerritCodeReview/plugins_delete-project,GerritCodeReview/plugins_delete-project