Add checkbox fields for review requests.

Review Request #9156 — Created Aug. 29, 2017 and submitted — Latest diff uploaded

David Trowbridge
Review Board

This change adds Python and JavaScript classes to add checkbox-type fields in
review requests. Extensions can use this very simply by just subclassing
BaseCheckboxField and providing field_id and label attributes. The
resulting boolean value will be stored in extra_data as expected.

  • Ran js-tests.
  • Ran unit tests.
  • Created a test extension that used a checkbox field and verified that the
    state was correctly rendered when loading the page and correctly stored when
    the checkbox was clicked.