message: Fix mixin summary support on variable declarations.
diff: @@ -58,10 +58,14 @@ class MixinVisitor implements Visitor {
  const namespacedName =
  name ? getNamespacedIdentifier(name, parentJsDocs) : undefined;
  const sourceRange = this._document.sourceRangeForNode(node);
  +
  + const summaryTag = jsdoc.getTag(parentJsDocs, 'summary');
  +
  this._currentMixin = new ScannedPolymerElementMixin({
  name: namespacedName,
  sourceRange,
  description: parentJsDocs.description,
  + summary: (summaryTag && summaryTag.description) || '',
  });
  this._currentMixinNode = node;
  this._mixins.push(this._currentMixin);
  