Add enables consistent with Chrome's WebKit

client/dom/generated/src/wrapping/_BlobWrappingImplementation.dart

 // Copyright (c) 2011, 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.
 
 // WARNING: Do not edit - generated code.
 
 class _BlobWrappingImplementation extends DOMWrapperBase implements Blob {
   _BlobWrappingImplementation() : super() {}
 
   static create__BlobWrappingImplementation() native {
     return new _BlobWrappingImplementation();
   }
 
   int get size() { return _get_size(this); }
   static int _get_size(var _this) native;
 
   String get type() { return _get_type(this); }
   static String _get_type(var _this) native;
 
+  Blob webkitSlice([int start = null, int end = null, String contentType = null]) {
+    if (start === null) {
+      if (end === null) {
+        if (contentType === null) {
+          return _webkitSlice(this);
+        }
+      }
+    } else {
+      if (end === null) {
+        if (contentType === null) {
+          return _webkitSlice_2(this, start);
+        }
+      } else {
+        if (contentType === null) {
+          return _webkitSlice_3(this, start, end);
+        } else {
+          return _webkitSlice_4(this, start, end, contentType);
+        }
+      }
+    }
+    throw "Incorrect number or type of arguments";
+  }
+  static Blob _webkitSlice(receiver) native;
+  static Blob _webkitSlice_2(receiver, start) native;
+  static Blob _webkitSlice_3(receiver, start, end) native;
+  static Blob _webkitSlice_4(receiver, start, end, contentType) native;
+
   String get typeName() { return "Blob"; }
 }