Revert "Revert "Blob constructor""

lib/html/frog/html_frog.dart

Index: lib/html/frog/html_frog.dart
diff --git a/lib/html/frog/html_frog.dart b/lib/html/frog/html_frog.dart
index b1dfc5bcf7e5537eaf9b2626996d2a371911bf17..dc0303521073a5837abc1777560ded92bf201a94 100644
--- a/lib/html/frog/html_frog.dart
+++ b/lib/html/frog/html_frog.dart
@@ -17130,6 +17130,30 @@ class _AudioElementFactoryProvider {
 // 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.
 
+class _BlobFactoryProvider {
+  factory Blob(List blobParts = null, [String type, String endings]) {
+    // TODO: validate that blobParts is a JS Array and convert if not.
+    // TODO: any coercions on the elements of blobParts, e.g. coerce a typed
+    // array to ArrayBuffer if it is a total view.
+    if (type == null && endings == null) {
+      return _create_1(blobParts);
+    }
+    var bag = _create_bag();
+    if (type != null) _bag_set(bag, 'type', type);
+    if (endings != null) _bag_set(bag, 'endings', endings);
+    return _create_2(blobParts, bag);
+  }
+
+  static _create_1(parts) native 'return new Blob(parts);';
+  static _create_2(parts, bag) native 'return new Blob(parts, bag);';
+
+  static _create_bag() native 'return {}';
+  static _bag_set(bag, key, value) native 'bag[key] = value;';
+}
+// Copyright (c) 2012, 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.
+
 class _CSSMatrixFactoryProvider {
   factory CSSMatrix([String cssValue = '']) native
       'return new WebKitCSSMatrix(cssValue);';
@@ -18560,7 +18584,9 @@ interface BiquadFilterNode extends AudioNode {
 // WARNING: Do not edit - generated code.
 
 /// @domName Blob
-interface Blob {
+interface Blob default _BlobFactoryProvider {
+
+  Blob(List blobParts, [String type, String endings]);
 
   /** @domName Blob.size */
   final int size;