anchor.diff:   */
   import "dart:html";
   import "../../testcommon.dart";
  -import "../../../Utils/async_utils.dart";
   
   main() {
     document.body.setInnerHtml('''
  
positive.code:   shouldBeTrue(customErrorFor("select-many-changes"));
    shouldBeTrue(customErrorFor("textarea-many-changes"));
    shouldBeTrue(customErrorFor("input-many-changes"));
    shouldBeTrue(customErrorFor("input-submit-many-changes"));*/
  
    debug('Set null.');
    for (var i = 0; i < v.length; i++)
      v[i].setCustomValidity(null);
    shouldBeFalse(customErrorFor("fieldset-many-changes"));
    shouldBeFalse(customErrorFor("button-many-changes"));
    shouldBeFalse(customErrorFor("button-button-many-changes"));
    shouldBeFalse(customErrorFor("button-reset-many-changes"));
    shouldBeFalse(customErrorFor("select-many-changes"));
    shouldBeFalse(customErrorFor("textarea-many-changes"));
    shouldBeFalse(customErrorFor("input-many-changes"));
    shouldBeFalse(customErrorFor("input-submit-many-changes"));
  
    /*debug('Set some value, and set undefined.');
    for (var i = 0; i < v.length; i++) {
      v[i].setCustomValidity("Custom string");
      v[i].setCustomValidity(undefined);
    }
    shouldBeFalse(customErrorFor("fieldset-many-changes"));
    shouldBeFalse(customErrorFor("button-many-changes"));
    shouldBeFalse(customErrorFor("button-button-many-changes"));
    shouldBeFalse(customErrorFor("button-reset-many-changes"));
    shouldBeFalse(customErrorFor("select-many-changes"));
    shouldBeFalse(customErrorFor("textarea-many-changes"));
    shouldBeFalse(customErrorFor("input-many-changes"));
    shouldBeFalse(customErrorFor("input-submit-many-changes"));*/
  }
  
negative.code:     v[i].setCustomValidity(null);
    }
    shouldBeFalse(customErrorFor("fieldset-many-changes"));
    shouldBeTrue(customErrorFor("button-many-changes"));
    shouldBeFalse(customErrorFor("button-button-many-changes"));
    shouldBeFalse(customErrorFor("button-reset-many-changes"));
    shouldBeTrue(customErrorFor("select-many-changes"));
    shouldBeTrue(customErrorFor("textarea-many-changes"));
    shouldBeTrue(customErrorFor("input-many-changes"));
    shouldBeTrue(customErrorFor("input-submit-many-changes"));
  
    debug('Set null.');
    for (var i = 0; i < v.length; i++)
      v[i].setCustomValidity(null);
    shouldBeFalse(customErrorFor("fieldset-many-changes"));
    shouldBeTrue(customErrorFor("button-many-changes"));
    shouldBeFalse(customErrorFor("button-button-many-changes"));
  