Repeats and fixes the changes landed & reverted as CL 1789553003.

tests/compiler/dart2js/codegen_helper.dart

-// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
+// Copyright (c) 2016, 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.
 
 import 'dart:async';
 import 'package:expect/expect.dart';
-import 'package:compiler/compiler_new.dart' show CompilerOptions;
+import 'package:compiler/src/options.dart' show CompilerOptions;
 import 'package:compiler/src/null_compiler_output.dart';
 import 'memory_source_file_helper.dart';
 
 Future<Map<String, String>> generate(String code,
     [List<String> options = const []]) {
   Uri script = currentDirectory.resolveUri(Platform.script);
   Uri libraryRoot = script.resolve('../../../sdk/');
   Uri packageRoot = script.resolve('./packages/');
 
   var provider = new MemorySourceFileProvider({ 'main.dart': code });
@@ skipping 14 matching lines @@
     var backend = compiler.backend;
     for (var element in backend.generatedCode.keys) {
       if (element.compilationUnit.script.readableUri != uri) continue;
       var name = element.name;
       var code = backend.getGeneratedCode(element);
       result[name] = code;
     }
     return result;
   });
 }