function assertStructureMatchesReference(element, referenceId) {
  assertStructureMatchesReferenceInner(element, getReferenceNode(referenceId));
}
Tests that the structure, node names, and classes of the given element are
the same as the reference structure with the given id. Throws an error if the
element doesn't have the same nodes at each level of the DOM with the same
classes on each. The test ignores all DOM structure within content nodes.
@param {?Node} element The root node of the DOM structure to test.
@param {string} referenceId The id of the container for the reference
    structure to test against.