Don't recreate CoreTypes in transformers. Pass it in.

pkg/kernel/test/baseline_tester.dart

 // 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:io';
 
 import 'package:analyzer/src/kernel/loader.dart';
 import 'package:kernel/application_root.dart';
+import 'package:kernel/core_types.dart';
 import 'package:kernel/kernel.dart';
 import 'package:kernel/target/targets.dart';
 import 'package:kernel/text/ast_to_text.dart';
 import 'package:kernel/verifier.dart';
 import 'package:path/path.dart' as pathlib;
 import 'package:test/test.dart';
 
 final String testcaseDirectory = 'pkg/kernel/testcases';
 final String inputDirectory = 'pkg/kernel/testcases/input';
 final String sdkDirectory = 'sdk';
 
 /// A target to be used for testing.
 ///
 /// To simplify testing dependencies, we avoid transformations that rely on
 /// a patched SDK or any SDK changes that have not landed in the main SDK.
 abstract class TestTarget extends Target {
   /// Annotations to apply on the textual output.
   Annotator get annotator => null;
 
   // Return a list of strings so that we can accumulate errors.
-  List<String> performModularTransformations(Program program);
-  List<String> performGlobalTransformations(Program program);
+  List<String> performModularTransformations(
+      CoreTypes coreTypes, Program program);
+  List<String> performGlobalTransformations(
+      CoreTypes coreTypes, Program program);
 }
 
 void runBaselineTests(String folderName, TestTarget target) {
   String outputDirectory = '$testcaseDirectory/$folderName';
   var batch = new DartLoaderBatch();
   Directory directory = new Directory(inputDirectory);
   var applicationRoot = new ApplicationRoot(directory.absolute.path);
   for (FileSystemEntity file in directory.listSync()) {
     if (file is File && file.path.endsWith('.dart')) {
       String name = pathlib.basename(file.path);
       test(name, () async {
         Uri dartPath =
             new Uri(scheme: 'file', path: pathlib.absolute(file.path));
         String shortName = pathlib.withoutExtension(name);
         String filenameOfBaseline = '$outputDirectory/$shortName.baseline.txt';
         String filenameOfCurrent = '$outputDirectory/$shortName.current.txt';
 
         var program = new Program();
+        var coreTypes = new CoreTypes(program);
         var loader = await batch.getLoader(
             program,
             new DartOptions(
                 strongMode: target.strongMode,
                 sdk: sdkDirectory,
                 declaredVariables: target.extraDeclaredVariables,
                 applicationRoot: applicationRoot));
         loader.loadProgram(dartPath, target: target);
         verifyProgram(program);
         var errors = <String>[];
-        errors.addAll(target.performModularTransformations(program));
+        errors.addAll(target.performModularTransformations(coreTypes, program));
         verifyProgram(program);
-        errors.addAll(target.performGlobalTransformations(program));
+        errors.addAll(target.performGlobalTransformations(coreTypes, program));
         verifyProgram(program);
 
         var buffer = new StringBuffer();
         for (var error in errors) {
           buffer.writeln('// $error');
         }
         new Printer(buffer, annotator: target.annotator)
             .writeLibraryFile(program.mainMethod.enclosingLibrary);
         String current = '$buffer';
         new File(filenameOfCurrent).writeAsStringSync(current);
 
         var baselineFile = new File(filenameOfBaseline);
         if (!baselineFile.existsSync()) {
           new File(filenameOfBaseline).writeAsStringSync(current);
         } else {
           var baseline = baselineFile.readAsStringSync();
           if (baseline != current) {
             fail('Output of `$name` changed for $folderName.\n'
                 'Command to reset the baseline:\n'
                 '  rm $filenameOfBaseline\n'
                 'Command to see the diff:\n'
                 '  diff -cd $outputDirectory/$shortName.{baseline,current}.txt'
                 '\n');
           }
         }
       });
     }
   }
 }