Deprecate all diagnostics methods that use strings.

pkg/front_end/lib/src/fasta/dill/dill_member_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_member_builder;
 
 import 'package:kernel/ast.dart'
     show Constructor, Field, Member, Procedure, ProcedureKind;
 
-import '../errors.dart' show internalError;
+import '../deprecated_problems.dart' show deprecated_internalProblem;
 
 import '../kernel/kernel_builder.dart'
     show
         Builder,
         MemberBuilder,
         isRedirectingGenerativeConstructorImplementation;
 
 import '../modifier.dart'
     show abstractMask, constMask, externalMask, finalMask, staticMask;
 
@@ skipping 49 matching lines @@
   if (member is Field) {
     modifier |= member.isConst ? constMask : 0;
     modifier |= member.isFinal ? finalMask : 0;
     modifier |= member.isStatic ? staticMask : 0;
   } else if (member is Procedure) {
     modifier |= member.isConst ? constMask : 0;
     modifier |= member.isStatic ? staticMask : 0;
   } else if (member is Constructor) {
     modifier |= member.isConst ? constMask : 0;
   } else {
-    internalError("Unhandled: ${member.runtimeType}");
+    deprecated_internalProblem("Unhandled: ${member.runtimeType}");
   }
   return modifier;
 }