Revert "Add cancelAnimationFrame"

tests/html/request_animation_frame_test.dart

Index: tests/html/request_animation_frame_test.dart
diff --git a/tests/html/request_animation_frame_test.dart b/tests/html/request_animation_frame_test.dart
index 15f6919f2130e6d986d46201ae8872e9c3a64fa3..62fb5d777f25d78290ec5a6bf2cd99e78aa40dce 100644
--- a/tests/html/request_animation_frame_test.dart
+++ b/tests/html/request_animation_frame_test.dart
@@ -17,38 +17,12 @@ main() {
 
   test('twoShot', () {
       var frame = window.requestAnimationFrame(
-          expectAsync1((timestamp1) {
+          (timestamp1) {
             window.requestAnimationFrame(
                 expectAsync1((timestamp2) {
-                    // Not monotonic on Safari and IE.
-                    // Expect.isTrue(timestamp2 > timestamp1, 'timestamps ordered');
-                  }));
-          }));
-    });
-
-
-  // How do we test that a callback is never called?  We can't wrap the uncalled
-  // callback with 'expectAsync1'.  Will request several frames and try
-  // cancelling the one that is not the last.
-  test('cancel1', () {
-      var frame1 = window.requestAnimationFrame(
-          (timestamp1) {
-            throw new Exception('Should have been cancelled');
-          });
-      var frame2 = window.requestAnimationFrame(
-          expectAsync1((timestamp2) { }));
-      window.cancelAnimationFrame(frame1);
-    });
-
-  test('cancel2', () {
-      var frame1 = window.requestAnimationFrame(
-          expectAsync1((timestamp1) { }));
-      var frame2 = window.requestAnimationFrame(
-          (timestamp2) {
-            throw new Exception('Should have been cancelled');
+                  // Not monotonic on Safari and IE.
+                  // Expect.isTrue(timestamp2 > timestamp1, 'timestamps ordered');
+                }));
           });
-      var frame3 = window.requestAnimationFrame(
-          expectAsync1((timestamp3) { }));
-      window.cancelAnimationFrame(frame2);
     });
 }