Start cleaning up the HTML tests.

pkg/dev_compiler/test/codegen/lib/html/util.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library test.html.util;
 
 import 'dart:html';
-import 'package:unittest/unittest.dart';
+import 'package:minitest/minitest.dart';
 
-void expectUnsupported(f) => expect(f, throwsUnsupportedError);
-
-void expectEmptyRect(ClientRect rect) {
-  expect(rect.bottom, isZero);
-  expect(rect.top, isZero);
-  expect(rect.left, isZero);
-  expect(rect.right, isZero);
-  expect(rect.height, isZero);
-  expect(rect.width, isZero);
+void expectEmptyRect(Rectangle rect) {
+  expect(rect.bottom, 0);
+  expect(rect.top, 0);
+  expect(rect.left, 0);
+  expect(rect.right, 0);
+  expect(rect.height, 0);
+  expect(rect.width, 0);
 }