Report compile-time errors on cyclic hierarchies.

pkg/front_end/lib/src/fasta/kernel/kernel_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.kernel_class_builder;
 
 import 'package:kernel/ast.dart'
     show
         Class,
         Constructor,
@@ skipping 250 matching lines @@
               declaredMember.fileOffset,
               "The method '$name::${declaredMember.name.name}' doesn't have "
               "the named parameter '${interfaceNamedParameters.current.name}' "
               "of overriden method '${interfaceMember.enclosingClass.name}::"
               "${interfaceMember.name.name}'.");
           break outer;
         }
       }
     }
   }
-
-  void addCompileTimeError(int charOffset, String message) {
-    library.addCompileTimeError(charOffset, message, fileUri: fileUri);
-  }
-
-  void addWarning(int charOffset, String message) {
-    library.addWarning(charOffset, message, fileUri: fileUri);
-  }
-
-  void addNit(int charOffset, String message) {
-    library.addNit(charOffset, message, fileUri: fileUri);
-  }
 }