Implement WebIDL method overloads. Fixes #540.

src/components/script/dom/blob.rs

@@ -0,0 +1,17 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use dom::bindings::utils::{WrapperCache};
+
+pub struct Blob {
+    wrapper: WrapperCache
+}
+
+impl Blob {
+    pub fn new() -> @mut Blob {
+        @mut Blob {
+            wrapper: WrapperCache::new()
+        }
+    }
+}