Introduce ConstructorEntity

pkg/compiler/lib/src/elements/entities.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 entities;
 
 import 'elements.dart' show Entity;
 
 /// Stripped down super interface for library like entities.
 ///
@@ skipping 35 matching lines @@
 }
 
 /// Stripped down super interface for field like entities.
 ///
 /// Currently only [FieldElement] but later also kernel based Dart fields
 /// and/or Dart-in-JS field-like properties.
 abstract class FieldEntity extends MemberEntity {}
 
 /// Stripped down super interface for function like entities.
 ///
-/// Currently only [FieldElement] but later also kernel based Dart constructors
+/// Currently only [MethodElement] but later also kernel based Dart constructors
 /// and methods and/or Dart-in-JS function-like properties.
 abstract class FunctionEntity extends MemberEntity {}
+
+/// Stripped down super interface for constructor like entities.
+///
+/// Currently only [ConstructorElement] but later also kernel based Dart
+/// constructors and/or Dart-in-JS constructor-like properties.
+// TODO(johnniwinther): Remove factory constructors from the set of
+// constructors.
+abstract class ConstructorEntity extends FunctionEntity {
+  bool get isGenerativeConstructor;
+  bool get isFactoryConstructor;
+}