Add MemberEntity.isAbstract and use MemberEntity in function_set.dart

pkg/compiler/lib/src/kernel/world_builder.dart

 // Copyright (c) 2017, 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.world_builder;
 
 import 'package:kernel/ast.dart' as ir;
 
 import '../common.dart';
 import '../common/backend_api.dart';
@@ skipping 213 matching lines @@
       KClass enclosingClass;
       if (node.enclosingClass != null) {
         enclosingClass = _getClass(node.enclosingClass);
         library = enclosingClass.library;
       } else {
         library = _getLibrary(node.enclosingLibrary);
       }
       Name name = getName(node.name);
       bool isStatic = node.isStatic;
       bool isExternal = node.isExternal;
+      bool isAbstract = node.isAbstract;
       KFunction function;
       switch (node.kind) {
         case ir.ProcedureKind.Factory:
           throw new UnsupportedError("Cannot create method from factory.");
         case ir.ProcedureKind.Getter:
           function = new KGetter(memberIndex, library, enclosingClass, name,
-              isStatic: isStatic, isExternal: isExternal);
+              isStatic: isStatic,
+              isExternal: isExternal,
+              isAbstract: isAbstract);
           break;
         case ir.ProcedureKind.Method:
         case ir.ProcedureKind.Operator:
           function = new KMethod(memberIndex, library, enclosingClass, name,
-              isStatic: isStatic, isExternal: isExternal);
+              isStatic: isStatic,
+              isExternal: isExternal,
+              isAbstract: isAbstract);
           break;
         case ir.ProcedureKind.Setter:
           function = new KSetter(
               memberIndex, library, enclosingClass, getName(node.name).setter,
-              isStatic: isStatic, isExternal: isExternal);
+              isStatic: isStatic,
+              isExternal: isExternal,
+              isAbstract: isAbstract);
           break;
       }
       _memberList.add(node);
       return function;
     });
   }
 
   KField _getField(ir.Field node) {
     return _fieldMap.putIfAbsent(node, () {
       int memberIndex = _memberList.length;
@@ skipping 646 matching lines @@
   }
 
   InterfaceType getMixinTypeForClass(KClass cls) {
     KClassEnv env = builder._classEnvs[cls.classIndex];
     ir.Supertype mixedInType = env.cls.mixedInType;
     if (mixedInType == null) return null;
     return builder.createInterfaceType(
         mixedInType.classNode, mixedInType.typeArguments);
   }
 }