code: function queueHostBindingForCheck(dirIndex) {
      // Must subtract the header offset because hostBindings functions are generated with
      // instructions that expect element indices that are NOT adjusted (e.g. elementProperty).
      ngDevMode &&
          assertEqual(firstTemplatePass, true, 'Should only be called in first template pass.');
      (tView.hostBindings || (tView.hostBindings = [])).push(dirIndex, viewData.length - 1 - HEADER_OFFSET);
  }
docs: Stores index of directive and host element so it will be queued for binding refresh during CD.