Add debug names to scopes.

pkg/front_end/lib/src/fasta/dill/dill_class_builder.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 fasta.dill_class_builder;
 
 import 'package:kernel/ast.dart' show Class, Member;
 
 import '../problems.dart' show unimplemented;
 
@@ skipping 12 matching lines @@
   DillClassBuilder(Class cls, DillLibraryBuilder parent)
       : cls = cls,
         super(
             null,
             computeModifiers(cls),
             cls.name,
             null,
             null,
             null,
             new Scope(<String, MemberBuilder>{}, <String, MemberBuilder>{},
-                parent.scope, isModifiable: false),
-            new Scope(<String, MemberBuilder>{}, null, null,
+                parent.scope, "class ${cls.name}", isModifiable: false),
+            new Scope(<String, MemberBuilder>{}, null, null, "constructors",
                 isModifiable: false),
             parent,
             cls.fileOffset);
 
   void addMember(Member member) {
     DillMemberBuilder builder = new DillMemberBuilder(member, this);
     String name = member.name.name;
     if (builder.isConstructor || builder.isFactory) {
       constructorScopeBuilder.addMember(name, builder);
     } else if (builder.isSetter) {
@@ skipping 10 matching lines @@
   KernelTypeBuilder get mixedInType => unimplemented("mixedInType", -1, null);
 
   void set mixedInType(KernelTypeBuilder mixin) {
     unimplemented("mixedInType=", -1, null);
   }
 }
 
 int computeModifiers(Class cls) {
   return cls.isAbstract ? abstractMask : 0;
 }