Add FrontEndStrategy, ResolutionFrontEndStrategy and KernelFrontEndStrategy

tests/compiler/dart2js/kernel/impact_test.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 dart2js.kernel.impact_test;
 
 import 'package:async_helper/async_helper.dart';
 import 'package:compiler/src/commandline_options.dart';
 import 'package:compiler/src/common.dart';
 import 'package:compiler/src/common/names.dart';
@@ skipping 675 matching lines @@
         entryPoint: entryPoint,
         memorySourceFiles: SOURCE,
         options: [
           fullTest ? Flags.analyzeAll : Flags.analyzeOnly,
           Flags.useKernel,
           Flags.enableAssertMessage
         ]);
     compiler.resolution.retainCachesForTesting = true;
     Expect.isTrue(await compiler.run(entryPoint));
     JavaScriptBackend backend = compiler.backend;
-    KernelElementAdapter kernelElementAdapter =
-        new KernelWorldBuilder(compiler.reporter, backend.kernelTask.program);
+    KernelWorldBuilder kernelElementAdapter =
+        new KernelWorldBuilder(compiler.reporter);
+    kernelElementAdapter.addProgram(backend.kernelTask.program);
 
     checkLibrary(compiler, kernelElementAdapter, compiler.mainApp,
         fullTest: fullTest);
     compiler.libraryLoader.libraries.forEach((LibraryElement library) {
       if (library == compiler.mainApp) return;
       checkLibrary(compiler, kernelElementAdapter, library, fullTest: fullTest);
     });
   });
 }
 
@@ skipping 182 matching lines @@
         visitList(type.optionalParameterTypes),
         type.namedParameters,
         visitList(type.namedParameterTypes));
   }
 }
 
 /// Perform unaliasing of all typedefs nested within a [ResolutionDartType].
 ResolutionDartType unalias(ResolutionDartType type) {
   return const Unaliaser().visit(type);
 }