Vendor dependencies

Let's see how I like this workflow.

vendor/wasm-bindgen/tests/headless/main.rs

@@ -0,0 +1,61 @@
+#![cfg(target_arch = "wasm32")]
+
+extern crate wasm_bindgen;
+extern crate wasm_bindgen_test;
+
+use wasm_bindgen::prelude::*;
+use wasm_bindgen_test::*;
+
+wasm_bindgen_test_configure!(run_in_browser);
+
+#[wasm_bindgen]
+pub struct ConsumeRetString;
+
+#[wasm_bindgen]
+impl ConsumeRetString {
+    // https://github.com/rustwasm/wasm-bindgen/issues/329#issuecomment-411082013
+    //
+    // This used to cause two `const ptr = ...` declarations, which is invalid
+    // JS.
+    pub fn consume(self) -> String {
+        String::new()
+    }
+}
+
+#[wasm_bindgen_test]
+fn works() {
+    ConsumeRetString.consume();
+}
+
+#[wasm_bindgen]
+extern "C" {
+    #[wasm_bindgen(js_namespace = console)]
+    pub fn log(s: &str);
+}
+
+#[wasm_bindgen_test]
+fn can_log_html_strings() {
+    log("<script>alert('lol')</script>");
+}
+
+#[wasm_bindgen]
+pub fn import_export_same_name() {
+    #[wasm_bindgen(module = "/tests/headless/main.js")]
+    extern "C" {
+        fn import_export_same_name();
+    }
+    import_export_same_name();
+}
+
+pub mod externref_heap_live_count;
+pub mod modules;
+pub mod snippets;
+pub mod strings;
+
+#[wasm_bindgen_test]
+fn closures_work() {
+    let x = Closure::wrap(Box::new(|| {}) as Box<dyn FnMut()>);
+    drop(x);
+    let x = Closure::wrap(Box::new(|| {}) as Box<dyn FnMut()>);
+    x.forget();
+}