Reify type params on map literals

test/codegen_expected/lib/html/event_customevent_test.js

 dart_library.library('lib/html/event_customevent_test', null, /* Imports */[
   'dart_sdk',
   'unittest'
 ], function load__event_customevent_test(exports, dart_sdk, unittest) {
   'use strict';
   const core = dart_sdk.core;
   const html = dart_sdk.html;
   const js = dart_sdk.js;
   const async = dart_sdk.async;
   const dart = dart_sdk.dart;
@@ skipping 18 matching lines @@
     constructors: () => ({new: dart.definiteFunctionType(event_customevent_test.DartPayloadData, [dart.dynamic])})
   });
   event_customevent_test.main = function() {
     html_config.useHtmlConfiguration();
     unittest$.test('custom events', dart.fn(() => {
       let provider = new (EventStreamProviderOfCustomEvent())('foo');
       let el = html.DivElement.new();
       let fired = false;
       provider.forTarget(el).listen(dart.fn(ev => {
         fired = true;
-        src__matcher__expect.expect(ev[dartx.detail], dart.map({type: 'detail'}));
+        src__matcher__expect.expect(ev[dartx.detail], dart.map({type: 'detail'}, core.String, core.String));
       }, CustomEventTovoid()));
-      let ev = html.CustomEvent.new('foo', {canBubble: false, cancelable: false, detail: dart.map({type: 'detail'})});
+      let ev = html.CustomEvent.new('foo', {canBubble: false, cancelable: false, detail: dart.map({type: 'detail'}, core.String, core.String)});
       el[dartx.dispatchEvent](ev);
       src__matcher__expect.expect(fired, src__matcher__core_matchers.isTrue);
     }, VoidTodynamic()));
     unittest$.test('custom events from JS', dart.fn(() => {
       let scriptContents = '      var event = document.createEvent("CustomEvent");\n      event.initCustomEvent("js_custom_event", true, true, {type: "detail"});\n      window.dispatchEvent(event);\n    ';
       let fired = false;
       html.window[dartx.on].get('js_custom_event').listen(dart.fn(ev => {
         fired = true;
-        src__matcher__expect.expect(dart.dload(ev, 'detail'), dart.map({type: 'detail'}));
+        src__matcher__expect.expect(dart.dload(ev, 'detail'), dart.map({type: 'detail'}, core.String, core.String));
       }, dynamicTovoid()));
       let script = html.ScriptElement.new();
       script[dartx.text] = scriptContents;
       html.document[dartx.body][dartx.append](script);
       src__matcher__expect.expect(fired, src__matcher__core_matchers.isTrue);
     }, VoidTodynamic()));
     unittest$.test('custom events to JS', dart.fn(() => {
       src__matcher__expect.expect(js.context.get('gotDartEvent'), src__matcher__core_matchers.isNull);
       let scriptContents = '      window.addEventListener(\'dart_custom_event\', function(e) {\n        if (e.detail == \'dart_message\') {\n          e.preventDefault();\n          window.gotDartEvent = true;\n        }\n        window.console.log(\'here\' + e.detail);\n      }, false);';
       html.document[dartx.body][dartx.append]((() => {
@@ skipping 12 matching lines @@
         src__matcher__expect.expect(dart.dload(event[dartx.detail], 'dartValue'), 666);
       }, dynamicTodynamic()));
       html.document[dartx.body][dartx.dispatchEvent](event);
       return future;
     }, VoidToFuture()));
   };
   dart.fn(event_customevent_test.main, VoidTodynamic());
   // Exports:
   exports.event_customevent_test = event_customevent_test;
 });