Copy lib/dom tests that use dart:html to lib/html.

tests/dom/instance_of_test.dart

-#library('InstanceOfTest');
-#import('../../lib/unittest/unittest.dart');
-#import('../../lib/unittest/html_config.dart');
-#import('dart:html');
-
-main() {
-  CanvasElement canvas;
-
-  canvas = new Element.tag('canvas');
-  canvas.attributes['width'] = 100;
-  canvas.attributes['height'] = 100;
-  document.body.nodes.add(canvas);
-
-  useHtmlConfiguration();
-  test('Instanceof', () {
-    Expect.isFalse(canvas is CanvasRenderingContext);
-    Expect.isFalse(canvas is CanvasRenderingContext2D);
-    Expect.isTrue(canvas is Element);
-    Expect.isTrue(canvas is CanvasElement);
-    Expect.isFalse(canvas is ImageData);
-    // Expect.isFalse(canvas is CanvasPixelArray);
-
-    CanvasRenderingContext2D context = canvas.getContext('2d');
-    Expect.isTrue(context is CanvasRenderingContext);
-    Expect.isTrue(context is CanvasRenderingContext2D);
-    Expect.isFalse(context is Element);
-    Expect.isFalse(context is CanvasElement);
-    Expect.isFalse(context is ImageData);
-    // Expect.isFalse(context is CanvasPixelArray);
-
-    // FIXME(b/5286633): Interface injection type check workaround.
-    var image = context.createImageData(canvas.width.dynamic, canvas.height.dynamic);
-    Expect.isFalse(image is CanvasRenderingContext);
-    Expect.isFalse(image is CanvasRenderingContext2D);
-    Expect.isFalse(image is Element);
-    Expect.isFalse(image is CanvasElement);
-    Expect.isTrue(image is ImageData);
-    // Expect.isFalse(image is CanvasPixelArray);
-
-    // Include CanvasPixelArray since constructor and prototype are not
-    // available until one is created.
-    var bytes = image.data;
-    Expect.isFalse(bytes is CanvasRenderingContext);
-    Expect.isFalse(bytes is CanvasRenderingContext2D);
-    Expect.isFalse(bytes is Element);
-    Expect.isFalse(bytes is CanvasElement);
-    Expect.isFalse(bytes is ImageData);
-    Expect.isTrue(bytes is Uint8ClampedArray);
-
-    // FIXME: Ensure this is an SpanElement when we next update
-    // WebKit IDL.
-    var span = new Element.tag('span');
-    Expect.isTrue(span is Element);
-  });
-}