New expectation functions plus convert old tests to use these.

tests/dom/canvas_test.dart

Index: tests/dom/canvas_test.dart
===================================================================
--- tests/dom/canvas_test.dart	(revision 8082)
+++ tests/dom/canvas_test.dart	(working copy)
@@ -34,7 +34,7 @@
     gradient.addColorStop(1,'blue');
     context.fillStyle = gradient;
     context.fillRect(0, 0, 20, 20);
-    expect(context.fillStyle is CanvasGradient).isTrue();
+    expect(context.fillStyle is CanvasGradient, isTrue());
   });
   test('SetFillColor', () {
     // With floats.