Refactor computation of NativeBehavior.

pkg/compiler/lib/src/native/enqueue.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.
 
 import '../common.dart';
 import '../common/backend_api.dart' show ForeignResolver;
 import '../common/resolution.dart' show Resolution;
 import '../compiler.dart' show Compiler;
 import '../constants/values.dart';
 import '../core_types.dart' show CommonElements;
@@ skipping 38 matching lines @@
 
   /// Process the potentially native [method]. Adds information from metadata
   /// attributes.
   void handleMethodAnnotations(Element method) {}
 
   /// Returns whether native classes are being used.
   bool get hasInstantiatedNativeClasses => false;
 
   /// Emits a summary information using the [log] function.
   void logSummary(log(message)) {}
-
-  // Do not use annotations in dart2dart.
-  ClassElement get annotationCreatesClass => null;
-  ClassElement get annotationReturnsClass => null;
-  ClassElement get annotationJsNameClass => null;
 }
 
 abstract class NativeEnqueuerBase implements NativeEnqueuer {
   static final RegExp _identifier = new RegExp(r'^[a-zA-Z_$][a-zA-Z0-9_$]*$');
 
   /// The set of all native classes.  Each native class is in [nativeClasses]
   /// and exactly one of [unusedClasses] and [registeredClasses].
   final Set<ClassElement> _nativeClasses = new Set<ClassElement>();
 
   final Set<ClassElement> _registeredClasses = new Set<ClassElement>();
   final Set<ClassElement> _unusedClasses = new Set<ClassElement>();
 
   bool get hasInstantiatedNativeClasses => !_registeredClasses.isEmpty;
 
   final Set<ClassElement> nativeClassesAndSubclasses = new Set<ClassElement>();
 
   final Compiler compiler;
   final bool enableLiveTypeAnalysis;
 
-  ClassElement _annotationCreatesClass;
-  ClassElement _annotationReturnsClass;
-  ClassElement _annotationJsNameClass;
-
   /// Subclasses of [NativeEnqueuerBase] are constructed by the backend.
   NativeEnqueuerBase(Compiler compiler, this.enableLiveTypeAnalysis)
       : this.compiler = compiler;
 
   JavaScriptBackend get backend => compiler.backend;
   BackendHelpers get helpers => backend.helpers;
   Resolution get resolution => compiler.resolution;
 
   DiagnosticReporter get reporter => compiler.reporter;
   CommonElements get commonElements => compiler.commonElements;
@@ skipping 152 matching lines @@
       }
       // Should be at '{', 'with', 'implements', '<' or 'native'.
       return id.value;
     }
 
     return reporter.withCurrentElement(classElement, () {
       return scanForExtendsName(classElement.position);
     });
   }
 
-  ClassElement get annotationCreatesClass {
-    findAnnotationClasses();
-    return _annotationCreatesClass;
-  }
-
-  ClassElement get annotationReturnsClass {
-    findAnnotationClasses();
-    return _annotationReturnsClass;
-  }
-
-  ClassElement get annotationJsNameClass {
-    findAnnotationClasses();
-    return _annotationJsNameClass;
-  }
-
-  void findAnnotationClasses() {
-    if (_annotationCreatesClass != null) return;
-
-    _annotationCreatesClass = helpers.annotationCreatesClass;
-    _annotationReturnsClass = helpers.annotationReturnsClass;
-    _annotationJsNameClass = helpers.annotationJSNameClass;
-  }
-
   /// Returns the JSName annotation string or `null` if no JSName annotation is
   /// present.
   String findJsNameFromAnnotation(Element element) {
     String name = null;
-    ClassElement annotationClass = annotationJsNameClass;
+    ClassElement annotationClass = backend.helpers.annotationJSNameClass;
     for (MetadataAnnotation annotation in element.implementation.metadata) {
       annotation.ensureResolved(resolution);
       ConstantValue value =
           compiler.constants.getConstantValue(annotation.constant);
       if (!value.isConstructedObject) continue;
       ConstructedConstantValue constructedObject = value;
       if (constructedObject.type.element != annotationClass) continue;
 
       Iterable<ConstantValue> fields = constructedObject.fields.values;
       // TODO(sra): Better validation of the constant.
@@ skipping 340 matching lines @@
     List<ClassEntity> directSubtypes =
         emitter.directSubtypes.putIfAbsent(superclass, () => <ClassEntity>[]);
     directSubtypes.add(cls);
   }
 
   void logSummary(log(message)) {
     log('Compiled ${_registeredClasses.length} native classes, '
         '${_unusedClasses.length} native classes omitted.');
   }
 }