Check in codegen test expectations.

test/codegen/expect/lib/html/js_interop_1_test.js

Index: test/codegen/expect/lib/html/js_interop_1_test.js
diff --git a/test/codegen/expect/lib/html/js_interop_1_test.js b/test/codegen/expect/lib/html/js_interop_1_test.js
new file mode 100644
index 0000000000000000000000000000000000000000..8c3999cf03a45256c68c2bb197bcef9a78ee364f
--- /dev/null
+++ b/test/codegen/expect/lib/html/js_interop_1_test.js
@@ -0,0 +1,42 @@
+dart_library.library('lib/html/js_interop_1_test', null, /* Imports */[
+  'dart_sdk',
+  'unittest'
+], function load__js_interop_1_test(exports, dart_sdk, unittest) {
+  'use strict';
+  const core = dart_sdk.core;
+  const html = dart_sdk.html;
+  const dart = dart_sdk.dart;
+  const dartx = dart_sdk.dartx;
+  const html_config = unittest.html_config;
+  const unittest$ = unittest.unittest;
+  const js_interop_1_test = Object.create(null);
+  let MessageEventTovoid = () => (MessageEventTovoid = dart.constFn(dart.functionType(dart.void, [html.MessageEvent])))();
+  let dynamicTodynamic = () => (dynamicTodynamic = dart.constFn(dart.definiteFunctionType(dart.dynamic, [dart.dynamic])))();
+  let VoidTobool = () => (VoidTobool = dart.constFn(dart.definiteFunctionType(core.bool, [])))();
+  let VoidTodynamic = () => (VoidTodynamic = dart.constFn(dart.definiteFunctionType(dart.dynamic, [])))();
+  js_interop_1_test.injectSource = function(code) {
+    let script = html.ScriptElement.new();
+    script[dartx.type] = 'text/javascript';
+    script[dartx.innerHtml] = core.String._check(code);
+    html.document[dartx.body][dartx.append](script);
+  };
+  dart.fn(js_interop_1_test.injectSource, dynamicTodynamic());
+  js_interop_1_test.main = function() {
+    html_config.useHtmlConfiguration();
+    let callback = null;
+    unittest$.test('js-to-dart-post-message', dart.fn(() => {
+      let subscription = null;
+      let complete = false;
+      subscription = html.window[dartx.onMessage].listen(MessageEventTovoid()._check(unittest$.expectAsyncUntil(dart.fn(e => {
+        if (dart.equals(dart.dload(e, 'data'), 'hello')) {
+          dart.dsend(subscription, 'cancel');
+          complete = true;
+        }
+      }, dynamicTodynamic()), dart.fn(() => complete, VoidTobool()))));
+      js_interop_1_test.injectSource("window.postMessage('hello', '*');");
+    }, VoidTodynamic()));
+  };
+  dart.fn(js_interop_1_test.main, VoidTodynamic());
+  // Exports:
+  exports.js_interop_1_test = js_interop_1_test;
+});