Support serialization of loadLibrary

tests/compiler/dart2js/js_spec_string_test.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 // Unit test of the [NativeBehavior.processSpecString] method.
 
 import 'package:expect/expect.dart';
 import 'package:compiler/src/native/native.dart';
 import 'package:compiler/src/diagnostics/diagnostic_listener.dart';
 import 'package:compiler/src/diagnostics/messages.dart';
 import 'package:compiler/src/universe/side_effects.dart'
     show SideEffects;
 
 const OBJECT = 'Object';
 const NULL = 'Null';
 
 class Listener extends DiagnosticReporter {
   String errorMessage;
   internalError(spannable, message) {
     errorMessage = message;
     throw "error";
   }
-  reportError(message, [infos]) {
 
+  reportError(message, [infos = const <DiagnosticMessage>[]]) {

[Johnni Winther, 2016/06/30 11:09:33]

Analyzer warnings that popped up during development. 

     errorMessage =
         '${message.message.arguments}'; // E.g.  "{text: Duplicate tag 'new'.}"
     throw "error";
   }
 
   @override
-  DiagnosticMessage createMessage(spannable, messageKind, [arguments]) {
+  DiagnosticMessage createMessage(spannable, messageKind,
+      [arguments = const {}]) {

[Johnni Winther, 2016/06/30 11:09:33]

Ditto

     return new DiagnosticMessage(null, spannable,
         MessageTemplate.TEMPLATES[messageKind].message(arguments));
   }
 
   noSuchMethod(_) => null;
 }
 
 void test(String specString,
           {List returns,
            List creates,
@@ skipping 263 matching lines @@
   test('gvn:false', expectedGvn: false);
   test('returns:A;gvn:true', returns: ['A'], expectedGvn: true);
   test(' gvn : true ;  returns:A;', returns: ['A'], expectedGvn: true);
   test('gvn:true;returns:A;gvn:true', expectError: true);
 
   test('gvn: true; new: true', expectError: true);
   test('gvn: true; new: false', expectedGvn: true, expectedNew: false);
   test('gvn: false; new: true', expectedGvn: false, expectedNew: true);
   test('gvn: false; new: false', expectedGvn: false, expectedNew: false);
 }