Vendor dependencies

Let's see how I like this workflow.

vendor/wasm-bindgen/tests/wasm/structural.rs

@@ -0,0 +1,32 @@
+use wasm_bindgen::prelude::*;
+use wasm_bindgen_test::*;
+
+#[wasm_bindgen(module = "tests/wasm/structural.js")]
+extern "C" {
+    fn js_works();
+}
+
+#[wasm_bindgen]
+extern "C" {
+    pub type StructuralFoo;
+
+    #[wasm_bindgen(method, structural)]
+    fn bar(this: &StructuralFoo);
+    #[wasm_bindgen(method, getter, structural)]
+    fn baz(this: &StructuralFoo) -> u32;
+    #[wasm_bindgen(method, setter, structural)]
+    fn set_baz(this: &StructuralFoo, val: u32);
+}
+
+#[wasm_bindgen]
+pub fn run(a: &StructuralFoo) {
+    a.bar();
+    assert_eq!(a.baz(), 1);
+    a.set_baz(2);
+    assert_eq!(a.baz(), 2);
+}
+
+#[wasm_bindgen_test]
+fn works() {
+    js_works();
+}