Split implementation of KernelToElementMapImpl

pkg/compiler/lib/src/compiler.dart

 // Copyright (c) 2012, 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 dart2js.compiler_base;
 
 import 'dart:async' show Future;
 
 import '../compiler_new.dart' as api;
 import 'backend_strategy.dart';
@@ skipping 174 matching lines @@
             : outputProvider {
     if (makeReporter != null) {
       _reporter = makeReporter(this, options);
     } else {
       _reporter = new CompilerDiagnosticReporter(this, options);
     }
     frontendStrategy = options.loadFromDill
         ? new KernelFrontEndStrategy(reporter, environment)
         : new ResolutionFrontEndStrategy(this);
     backendStrategy = options.loadFromDill
-        ? new KernelBackendStrategyImpl(this)
+        ? new KernelBackendStrategy(this)
         : new ElementBackendStrategy(this);
     _resolution = createResolution();
 
     if (options.verbose) {
       progress = new Stopwatch()..start();
     }
 
     backend = createBackend();
     enqueuer = backend.makeEnqueuer();
 
@@ skipping 1388 matching lines @@
   _ElementScanner(this.scanner);
   void scanLibrary(LibraryElement library) => scanner.scanLibrary(library);
   void scanUnit(CompilationUnitElement unit) => scanner.scan(unit);
 }
 
 class _EmptyEnvironment implements Environment {
   const _EmptyEnvironment();
 
   String valueOf(String key) => null;
 }