Use memory compiler in compiler_helper.dart.

tests/compiler/dart2js/frontend_checker.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.
 
 // Checks that dart2js produces the expected static type warnings and
 // compile-time errors for the provided multitests.
 
 import 'dart:async';
 import 'dart:io';
 
 import 'package:async_helper/async_helper.dart';
+import 'package:compiler/src/commandline_options.dart';
 import 'package:compiler/src/util/uri_extras.dart'
     show relativize;
 import 'memory_compiler.dart';
 
 import '../../../tools/testing/dart/multitest.dart'
     show ExtractTestsFromMultitest;
 import '../../../tools/testing/dart/path.dart'
     show Path;
 
 
@@ skipping 20 matching lines @@
     ExtractTestsFromMultitest(new Path(fileName), testSources, testOutcomes);
     return Future.forEach(testSources.keys, (String testName) async {
       String testFileName = '$fileName/$testName';
       Set<String> expectedOutcome = testOutcomes[testName];
       bool expectFailure = testFiles[testFile].contains(testName);
       DiagnosticCollector collector = new DiagnosticCollector();
       CompilationResult result = await runCompiler(
           entryPoint: Uri.parse('memory:$testFileName'),
           memorySourceFiles: {testFileName: testSources[testName]},
           diagnosticHandler: collector,
-          options: ['--analyze-only']..addAll(options),
+          options: [Flags.analyzeOnly]..addAll(options),
           showDiagnostics: verbose,
           cachedCompiler: cachedCompiler);
       var compiler = result.compiler;
       bool unexpectedResult = false;
       if (expectedOutcome.contains('compile-time error')) {
         if (collector.errors.isEmpty) {
           print('$testFileName: Missing compile-time error.');
           unexpectedResult = true;
         }
       } else if (expectedOutcome.contains('static type warning')) {
@@ skipping 38 matching lines @@
 === ERROR: Unexpected result of analysis.
 ===
 === Please update the white-listing in $testFileName
 ===
 
 ''');
       exit(1);
     }
   }));
 }