Check in codegen test expectations.

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

Index: test/codegen/expect/lib/html/shadowroot_test.js
diff --git a/test/codegen/expect/lib/html/shadowroot_test.js b/test/codegen/expect/lib/html/shadowroot_test.js
new file mode 100644
index 0000000000000000000000000000000000000000..3b2a651d80cfc5beae70548f62dcf0e981c3eea7
--- /dev/null
+++ b/test/codegen/expect/lib/html/shadowroot_test.js
@@ -0,0 +1,37 @@
+dart_library.library('lib/html/shadowroot_test', null, /* Imports */[
+  'dart_sdk',
+  'unittest'
+], function load__shadowroot_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 src__matcher__core_matchers = unittest.src__matcher__core_matchers;
+  const unittest$ = unittest.unittest;
+  const src__matcher__expect = unittest.src__matcher__expect;
+  const src__matcher__throws_matcher = unittest.src__matcher__throws_matcher;
+  const shadowroot_test = Object.create(null);
+  let dynamicTobool = () => (dynamicTobool = dart.constFn(dart.definiteFunctionType(core.bool, [dart.dynamic])))();
+  let VoidToShadowRoot = () => (VoidToShadowRoot = dart.constFn(dart.definiteFunctionType(html.ShadowRoot, [])))();
+  let VoidTodynamic = () => (VoidTodynamic = dart.constFn(dart.definiteFunctionType(dart.dynamic, [])))();
+  shadowroot_test.main = function() {
+    html_config.useHtmlConfiguration();
+    let isShadowRoot = src__matcher__core_matchers.predicate(dart.fn(x => html.ShadowRoot.is(x), dynamicTobool()), 'is a ShadowRoot');
+    unittest$.test('ShadowRoot supported', dart.fn(() => {
+      let isSupported = html.ShadowRoot[dartx.supported];
+      if (dart.test(isSupported)) {
+        let div = html.DivElement.new();
+        let shadowRoot = div[dartx.createShadowRoot]();
+        src__matcher__expect.expect(shadowRoot, isShadowRoot);
+        src__matcher__expect.expect(div[dartx.shadowRoot], shadowRoot);
+      } else {
+        src__matcher__expect.expect(dart.fn(() => html.DivElement.new()[dartx.createShadowRoot](), VoidToShadowRoot()), src__matcher__throws_matcher.throws);
+      }
+    }, VoidTodynamic()));
+  };
+  dart.fn(shadowroot_test.main, VoidTodynamic());
+  // Exports:
+  exports.shadowroot_test = shadowroot_test;
+});