Check in codegen test expectations.

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

+dart_library.library('lib/html/storage_test', null, /* Imports */[
+  'dart_sdk',
+  'unittest'
+], function load__storage_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 src__matcher__expect = unittest.src__matcher__expect;
+  const src__matcher__core_matchers = unittest.src__matcher__core_matchers;
+  const storage_test = Object.create(null);
+  let VoidTodynamic = () => (VoidTodynamic = dart.constFn(dart.definiteFunctionType(dart.dynamic, [])))();
+  storage_test.main = function() {
+    html_config.useHtmlConfiguration();
+    unittest$.test('GetItem', dart.fn(() => {
+      let value = html.window[dartx.localStorage][dartx.get]('does not exist');
+      src__matcher__expect.expect(value, src__matcher__core_matchers.isNull);
+    }, VoidTodynamic()));
+    unittest$.test('SetItem', dart.fn(() => {
+      let key = 'foo';
+      let value = 'bar';
+      html.window[dartx.localStorage][dartx.set](key, value);
+      let stored = html.window[dartx.localStorage][dartx.get](key);
+      src__matcher__expect.expect(stored, value);
+    }, VoidTodynamic()));
+    unittest$.test('event', dart.fn(() => {
+      let event = html.StorageEvent.new('something', {oldValue: 'old', newValue: 'new', url: 'url', key: 'key'});
+      src__matcher__expect.expect(html.StorageEvent.is(event), src__matcher__core_matchers.isTrue);
+      src__matcher__expect.expect(event[dartx.oldValue], 'old');
+      src__matcher__expect.expect(event[dartx.newValue], 'new');
+    }, VoidTodynamic()));
+  };
+  dart.fn(storage_test.main, VoidTodynamic());
+  // Exports:
+  exports.storage_test = storage_test;
+});