dart2js: Trust type annotations more often with --trust-type-annotation.

tests/compiler/dart2js/compiler_helper.dart

 // Copyright (c) 2012, 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.
 
 library compiler_helper;
 
 import 'dart:async';
 import "package:expect/expect.dart";
 
 import 'package:compiler/src/elements/elements.dart'
@@ skipping 93 matching lines @@
       trustTypeAnnotations: trustTypeAnnotations,
       expectedErrors: expectedErrors,
       expectedWarnings: expectedWarnings);
   compiler.registerSource(uri, code);
   return compiler;
 }
 
 Future<String> compileAll(String code,
                           {Map<String, String> coreSource,
                           bool disableInlining: true,
+                          bool trustTypeAnnotations: false,
                           bool minify: false,
                           int expectedErrors,
                           int expectedWarnings}) {
   Uri uri = new Uri(scheme: 'source');
   MockCompiler compiler = compilerFor(
       code, uri, coreSource: coreSource, disableInlining: disableInlining,
       minify: minify, expectedErrors: expectedErrors,
+      trustTypeAnnotations: trustTypeAnnotations,
       expectedWarnings: expectedWarnings);
   return compiler.runCompiler(uri).then((_) {
     Expect.isFalse(compiler.compilationFailed,
                    'Unexpected compilation error(s): ${compiler.errors}');
     return compiler.assembledCode;
   });
 }
 
 Future compileAndCheck(String code,
                        String name,
@@ skipping 120 matching lines @@
     regexp = regexp.replaceAll(xRe, '(?:$anyIdentifier)');
     final spaceRe = new RegExp('\\s+');
     regexp = regexp.replaceAll(spaceRe, '(?:\\s*)');
     if (shouldMatch) {
       Expect.isTrue(new RegExp(regexp).hasMatch(generated));
     } else {
       Expect.isFalse(new RegExp(regexp).hasMatch(generated));
     }
   });
 }