Add support for compiling Dart via the FE in dart2js.

pkg/compiler/lib/src/js_backend/backend.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 js_backend.backend;
 
 import '../common.dart';
 import '../common/backend_api.dart'
     show ForeignResolver, NativeRegistry, ImpactTransformer;
 import '../common/codegen.dart' show CodegenWorkItem;
@@ skipping 425 matching lines @@
 
   Target _target;
 
   Tracer tracer;
 
   JavaScriptBackend(this.compiler,
       {bool generateSourceMap: true,
       bool useStartupEmitter: false,
       bool useMultiSourceInfo: false,
       bool useNewSourceInfo: false,
-      bool useKernel: false})
+      bool useKernelInSsa: false})
       : optimizerHints = new OptimizerHintsForTests(
             compiler.frontendStrategy.elementEnvironment,
             compiler.frontendStrategy.commonElements),
         this.sourceInformationStrategy =
             compiler.backendStrategy.sourceInformationStrategy,
         constantCompilerTask = new JavaScriptConstantTask(compiler),
         _nativeDataResolver = new NativeDataResolverImpl(compiler) {
     CommonElements commonElements = compiler.frontendStrategy.commonElements;
     _target = new JavaScriptBackendTarget(this);
     _mirrorsData = compiler.frontendStrategy.createMirrorsDataBuilder();
@@ skipping 909 matching lines @@
 
   bool canUseAliasedSuperMember(MemberEntity member, Selector selector) {
     return !selector.isGetter;
   }
 
   /// Returns `true` if [member] is called from a subclass via `super`.
   bool isAliasedSuperMember(MemberEntity member) {
     return _aliasedSuperMembers.contains(member);
   }
 }