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

pkg/kernel/lib/transformations/mixin_full_resolution.dart

Index: pkg/kernel/lib/transformations/mixin_full_resolution.dart
diff --git a/pkg/kernel/lib/transformations/mixin_full_resolution.dart b/pkg/kernel/lib/transformations/mixin_full_resolution.dart
index 0fbb388f8781ac254283066388e11f39c8a2aeb5..749ffeacf7aae06f5509e70b32bf64c767ddaf70 100644
--- a/pkg/kernel/lib/transformations/mixin_full_resolution.dart
+++ b/pkg/kernel/lib/transformations/mixin_full_resolution.dart
@@ -10,8 +10,8 @@ import '../core_types.dart';
 import '../target/targets.dart' show NoneTarget, Target;
 import '../type_algebra.dart';
 
-Program transformProgram(Program program) {
-  new MixinFullResolution(new NoneTarget(null)).transform(program);
+Program transformProgram(CoreTypes coreTypes, Program program) {
+  new MixinFullResolution(new NoneTarget(null), coreTypes).transform(program);
   return program;
 }
 
@@ -24,10 +24,10 @@ Program transformProgram(Program program) {
 class MixinFullResolution {
   final Target targetInfo;
 
+  final CoreTypes coreTypes;
   ClassHierarchy hierarchy;
-  CoreTypes coreTypes;
 
-  MixinFullResolution(this.targetInfo);
+  MixinFullResolution(this.targetInfo, this.coreTypes);
 
   void transform(Program program) {
     var transformedClasses = new Set<Class>();
@@ -44,7 +44,6 @@ class MixinFullResolution {
     }
 
     hierarchy = new ClassHierarchy(program);
-    coreTypes = new CoreTypes(program);
 
     // Resolve all super call expressions and super initializers.
     for (var library in program.libraries) {