message: Didn't need to remove that whitespace.  Put it back.
diff: @@ -188,6 +188,7 @@ export class Bundler {
  bundleImports?: Set<string>): Promise<ASTNode> {
  const docUrl = docBundle.url;
  const document = await this._prepareBundleDocument(docBundle);
  +
  this._appendHtmlImportsForBundle(document, docBundle);
  importUtils.rewriteDocumentToEmulateBaseTag(docUrl, document);
  