Split implementation of KernelToElementMapImpl

pkg/compiler/lib/src/universe/resolution_world_builder.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 file.
 
 part of world_builder;
 
 abstract class ResolutionWorldBuilder implements WorldBuilder, OpenWorld {
   /// Set of all local functions in the program. Used by the mirror tracking
   /// system to find all live closure instances.
   Iterable<Local> get localFunctions;
@@ skipping 916 matching lines @@
     forEachInstantiatedClass(addSubtypes);
 
     _classHierarchyNodes.keys.toList().forEach(_ensureClassSet);
 
     return typesImplementedBySubclasses;
   }
 }
 
 abstract class KernelResolutionWorldBuilderBase
     extends ResolutionWorldBuilderBase {
-  KernelToElementMapImpl get elementMap;
+  KernelToElementMapForImpactImpl get elementMap;
 
   KernelResolutionWorldBuilderBase(
       ElementEnvironment elementEnvironment,
       DartTypes dartTypes,
       CommonElements commonElements,
       ConstantSystem constantSystem,
       NativeBasicData nativeBasicData,
       NativeDataBuilder nativeDataBuilder,
       InterceptorDataBuilder interceptorDataBuilder,
       BackendUsageBuilder backendUsageBuilder,
@@ skipping 35 matching lines @@
         typesImplementedBySubclasses: typesImplementedBySubclasses,
         classHierarchyNodes: _classHierarchyNodes,
         classSets: _classSets);
   }
 
   @override
   void registerClass(ClassEntity cls) {
     throw new UnimplementedError('KernelResolutionWorldBuilder.registerClass');
   }
 }