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

pkg/kernel/test/reify/suite.dart

 // Copyright (c) 2017, 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.md file.
 
 library test.kernel.reify.suite;
 
 import 'dart:async' show Future;
 
 import 'dart:io' show Directory, File, Platform;
 
 import 'package:analyzer/src/generated/sdk.dart' show DartSdk;
 
 import 'package:analyzer/src/kernel/loader.dart'
     show DartLoader, DartOptions, createDartSdk;
 
+import 'package:kernel/core_types.dart' show CoreTypes;
+
 import 'package:kernel/target/targets.dart' show Target, TargetFlags, getTarget;
 
 import 'package:kernel/target/vmcc.dart' show VmClosureConvertedTarget;
 
 import 'kernel_chain.dart'
     show MatchExpectation, Print, ReadDill, SanityCheck, WriteDill;
 
 import 'package:testing/testing.dart'
     show
         Chain,
@@ skipping 119 matching lines @@
 
   @override
   String get name => "not reified target";
 
   // Tree shaking needs to be disabled, because Generic Types Reification
   // transformation relies on certain runtime libraries to be present in
   // the program that is being transformed. If the tree shaker is enabled,
   // it just deletes everything from those libraries, because they aren't
   // used in the program being transform prior to the transformation.
   @override
-  void performTreeShaking(Program program) {}
+  void performTreeShaking(CoreTypes coreTypes, Program program) {}
 
   // Erasure needs to be disabled, because it removes the necessary information
   // about type arguments for generic methods.
   @override
   void performErasure(Program program) {}
 
   // Adds the necessary runtime libraries.
   @override
   List<String> get extraRequiredLibraries {
     Target reifyTarget = getTarget("vmreify", this.flags);
@@ skipping 18 matching lines @@
           strongMode: true,
           kernelRuntime: Platform.script.resolve("../../runtime/")));
 
       String path = description.file.path;
       Uri uri = Uri.base.resolve(path);
       loader.loadProgram(uri, target: target);
       var program = loader.program;
       for (var error in loader.errors) {
         return fail(program, "$error");
       }
+      var coreTypes = new CoreTypes(program);
       target
-        ..performModularTransformations(program)
-        ..performGlobalTransformations(program);
+        ..performModularTransformations(coreTypes, program)
+        ..performGlobalTransformations(coreTypes, program);
       return pass(program);
     } catch (e, s) {
       return crash(e, s);
     }
   }
 }
 
 class GenericTypesReification extends Step<Program, Program, TestContext> {
   const GenericTypesReification();
 
   String get name => "generic types reification";
 
   Future<Result<Program>> run(Program program, TestContext testContext) async {
     try {
-      program = generic_types_reification.transformProgram(program);
+      CoreTypes coreTypes = new CoreTypes(program);
+      program = generic_types_reification.transformProgram(coreTypes, program);
       return pass(program);
     } catch (e, s) {
       return crash(e, s);
     }
   }
 }
 
 class Run extends Step<Uri, int, TestContext> {
   const Run();
 
   String get name => "run";
 
   Future<Result<int>> run(Uri uri, TestContext context) async {
     File generated = new File.fromUri(uri);
     StdioProcess process;
     try {
       process =
           await StdioProcess.run(context.vm.toFilePath(), [generated.path]);
       print(process.output);
     } finally {
       generated.parent.delete(recursive: true);
     }
     return process.toResult();
   }
 }
 
 main(List<String> arguments) => runMe(arguments, createContext, "testing.json");