message: Added a cloneTree method to ast-utils so we have a safe way to create new asts from old asts.
diff: */
  import * as dom5 from 'dom5';
  -import {ASTNode} from 'parse5';
  +import {ASTNode, parse, serialize} from 'parse5';
  import * as matchers from './matchers';
  +/**
  + * Creates a clone of the AST. The clone is hygenic, by reparsing the
  + * serialized form of the given AST.
  + */
  +export function cloneTree(ast: ASTNode): ASTNode {
  + return parse(serialize(ast));
  +}
  +
  /**
  * Move the `node` to be the immediate sibling after the `target` node.
  * TODO(usergenic): Migrate this code to polymer/dom5 and when you do, use
  