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

pkg/kernel/lib/transformations/reify/reify_transformer.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.
 
 library kernel.transformations.reify.standalone_runner;
 
 import 'analysis/program_analysis.dart';
 import 'dart:io' show File, IOSink;
 
 import 'package:kernel/binary/ast_to_binary.dart' show BinaryPrinter;
@@ skipping 23 matching lines @@
     return candidates.single;
   }
 
   Library types = findLibraryEndingWith("reify/types.dart");
   Library declarations = findLibraryEndingWith("reify/declarations.dart");
   Library interceptors = findLibraryEndingWith("reify/interceptors.dart");
   return new RuntimeLibrary(types, declarations, interceptors);
 }
 
 Program transformProgramUsingLibraries(
-    Program program, RuntimeLibrary runtimeLibrary,
+    CoreTypes coreTypes, Program program, RuntimeLibrary runtimeLibrary,
     [Library libraryToTransform]) {
   LibraryFilter filter = libraryToTransform != null
       ? (Library library) => library == libraryToTransform
       : (_) => true;
   ProgramKnowledge knowledge = analyze(program, analyzeLibrary: filter);
   Library mainLibrary = program.mainMethod.parent;
-  RuntimeTypeSupportBuilder builder = new RuntimeTypeSupportBuilder(
-      runtimeLibrary, new CoreTypes(program), mainLibrary);
+  RuntimeTypeSupportBuilder builder =
+      new RuntimeTypeSupportBuilder(runtimeLibrary, coreTypes, mainLibrary);
   ReifyVisitor transformer =
       new ReifyVisitor(runtimeLibrary, builder, knowledge, libraryToTransform);
   // Transform the main program.
   program = program.accept(transformer);
   if (!filter(runtimeLibrary.interceptorsLibrary)) {
     // We need to transform the interceptor function in any case to make sure
     // that the type literals in the interceptor function are rewritten.
     runtimeLibrary.interceptorFunction.accept(transformer);
   }
   builder.createDeclarations();
   program = program.accept(new Erasure(transformer));
   // TODO(karlklose): skip checks in debug mode
   verifyProgram(program);
   return program;
 }
 
-Program transformProgram(Program program) {
+Program transformProgram(CoreTypes coreTypes, Program program) {
   RuntimeLibrary runtimeLibrary = findRuntimeTypeLibrary(program);
   Library mainLibrary = program.mainMethod.enclosingLibrary;
-  return transformProgramUsingLibraries(program, runtimeLibrary, mainLibrary);
+  return transformProgramUsingLibraries(
+      coreTypes, program, runtimeLibrary, mainLibrary);
 }
 
 main(List<String> arguments) async {
   String path = arguments.first;
   Uri output;
   if (arguments.length > 1) {
     output = Uri.base.resolve(arguments[1]);
   }
   Uri uri = Uri.base.resolve(path);
   Program program = loadProgramFromBinary(uri.toFilePath());
+  CoreTypes coreTypes = new CoreTypes(program);
 
   RuntimeLibrary runtimeLibrary = findRuntimeTypeLibrary(program);
   Library mainLibrary = program.mainMethod.enclosingLibrary;
-  program =
-      transformProgramUsingLibraries(program, runtimeLibrary, mainLibrary);
+  program = transformProgramUsingLibraries(
+      coreTypes, program, runtimeLibrary, mainLibrary);
 
   if (output == null) {
     // Print result
     StringBuffer sb = new StringBuffer();
     Printer printer = new Printer(sb);
     printer.writeLibraryFile(mainLibrary);
     print("$sb");
   } else {
     IOSink sink = new File.fromUri(output).openWrite();
     try {
       new BinaryPrinter(sink).writeProgramFile(program);
     } finally {
       await sink.close();
     }
     try {
       // Check that we can read the binary file.
       loadProgramFromBinary(output.toFilePath());
     } catch (e) {
       print("Error when attempting to read $output.");
       rethrow;
     }
   }
 }