Split backend implementation of EnqueuerListener

pkg/compiler/lib/src/js_emitter/program_builder/program_builder.dart

 // Copyright (c) 2014, 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.js_emitter.program_builder;
 
 import '../../closure.dart' show ClosureFieldElement;
 import '../../common.dart';
 import '../../common/names.dart' show Names, Selectors;
 import '../../compiler.dart' show Compiler;
@@ skipping 172 matching lines @@
     List<js.TokenFinalizer> finalizers = [_task.metadataCollector];
     if (backend.namer is js.TokenFinalizer) {
       var namingFinalizer = backend.namer;
       finalizers.add(namingFinalizer as js.TokenFinalizer);
     }
 
     return new Program(fragments, holders, _buildLoadMap(), _symbolsMap,
         _buildTypeToInterceptorMap(), _task.metadataCollector, finalizers,
         needsNativeSupport: needsNativeSupport,
         outputContainsConstantList: collector.outputContainsConstantList,
-        hasIsolateSupport: backend.hasIsolateSupport);
+        hasIsolateSupport: backend.backendUsage.isIsolateInUse);
   }
 
   void _markEagerClasses() {
     _markEagerInterceptorClasses();
   }
 
   /// Builds a map from loadId to outputs-to-load.
   Map<String, List<Fragment>> _buildLoadMap() {
     Map<String, List<Fragment>> loadMap = <String, List<Fragment>>{};
     _compiler.deferredLoadTask.hunksToLoad
@@ skipping 448 matching lines @@
 
   bool _methodNeedsStubs(FunctionElement method) {
     return !method.functionSignature.optionalParameters.isEmpty;
   }
 
   bool _methodCanBeReflected(FunctionElement method) {
     return backend.mirrorsData.isAccessibleByReflection(method);
   }
 
   bool _methodCanBeApplied(FunctionElement method) {
-    return backend.hasFunctionApplySupport &&
+    return backend.backendUsage.isFunctionApplyUsed &&
         closedWorld.getMightBePassedToApply(method);
   }
 
   /* Map | List */ _computeParameterDefaultValues(FunctionSignature signature) {
     var /* Map | List */ optionalParameterDefaultValues;
     if (signature.optionalParametersAreNamed) {
       optionalParameterDefaultValues = new Map<String, ConstantValue>();
       signature.forEachOptionalParameter((ParameterElement parameter) {
         ConstantValue def =
             backend.constants.getConstantValue(parameter.constant);
@@ skipping 293 matching lines @@
       Constant constant = new Constant(name, holder, constantValue);
       _constants[constantValue] = constant;
     }
   }
 
   Holder _registerStaticStateHolder() {
     return _registry.registerHolder(namer.staticStateHolder,
         isStaticStateHolder: true);
   }
 }