Move minitest.dart into the expect package.

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

 // Copyright (c) 2013, 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
 
 import 'dart:html';
 
-import 'package:minitest/minitest.dart';
+import 'package:expect/minitest.dart';
 
 main() {
   var isElement = predicate((x) => x is Element, 'is an Element');
   var isCanvasElement =
       predicate((x) => x is CanvasElement, 'is a CanvasElement');
   var isDivElement = predicate((x) => x is DivElement, 'is a isDivElement');
 
   var div = new DivElement();
   div.id = 'test';
   document.body.nodes.add(div);
@@ skipping 233 matching lines @@
       for (Element elem in all1) {
         expect(elem.contentEdge.height, 200);
       }
       all1.contentEdge.height = new Dimension.px(10);
       for (Element elem in all1) {
         expect(elem.contentEdge.height, 10);
       }
     });
   });
 }