Making FormData able to add Blobs and Files.

tests/html/form_data_test.dart

Index: tests/html/form_data_test.dart
diff --git a/tests/html/form_data_test.dart b/tests/html/form_data_test.dart
index 61f01477d4f6af88cb6900ee550e0e0cf7566527..6ea53810970239f06301717ad1c3bdba4d55b09f 100644
--- a/tests/html/form_data_test.dart
+++ b/tests/html/form_data_test.dart
@@ -29,10 +29,18 @@ void main() {
 
   test('appendTest', () {
     var form = new FormData();
-    form.append('test', '1', 'foo');
-    form.append('username', 'Elmo', 'foo');
-    form.append('address', '1 Sesame Street', 'foo');
+    form.append('test', '1');
+    form.append('username', 'Elmo');
+    form.append('address', '1 Sesame Street');
     form.append('password', '123456', 'foo');
     expect(form, isNotNull);
   });
+
+  test('appendBlob', () {
+    var form = new FormData();
+    var blob = new Blob(
+        ['Indescribable... Indestructible! Nothing can stop it!'],
+        'text/plain');
+    form.append('theBlob', blob, 'theBlob.txt');
+  });
 }