Add extends attributes for several types

Part of #670

crates/js-sys/tests/wasm/DataView.rs

@@ -1,5 +1,6 @@
 use wasm_bindgen::JsValue;
 use wasm_bindgen_test::*;
+use wasm_bindgen::JsCast;
 use js_sys::*;
 
 #[wasm_bindgen_test]
@@ -37,3 +38,16 @@ fn test() {
     // TODO: figure out how to do `bytes[2]`
     bytes.subarray(2, 3).for_each(&mut |x, _, _| assert_eq!(x, 42));
 }
+
+#[wasm_bindgen_test]
+fn dataview_inheritance() {
+    let bytes = Int8Array::new(&JsValue::from(10));
+
+    // TODO: figure out how to do `bytes[2] = 2`
+    bytes.subarray(2, 3).fill(2, 0, 1);
+
+    let v = DataView::new(&bytes.buffer(), 2, 8);
+
+    assert!(v.is_instance_of::<DataView>());
+    assert!(v.is_instance_of::<Object>());
+}