Implement character offsets for fields and enum constants.

pkg/front_end/lib/src/fasta/kernel/kernel_library_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_library_builder;
 
 import 'package:kernel/ast.dart';
 
 import 'package:kernel/clone.dart' show CloneVisitor;
 
@@ skipping 230 matching lines @@
         nativeMethodName,
         redirectionTarget);
     currentDeclaration.addFactoryDeclaration(procedure, factoryDeclaration);
     addBuilder(name, procedure, charOffset);
     if (nativeMethodName != null) {
       addNativeMethod(procedure);
     }
   }
 
   void addEnum(List<MetadataBuilder> metadata, String name,
-      List<String> constants, int charOffset, int charEndOffset) {
+      List<Object> constantNamesAndOffsets, int charOffset, int charEndOffset) {
     addBuilder(
         name,
-        new KernelEnumBuilder(
-            metadata, name, constants, this, charOffset, charEndOffset),
+        new KernelEnumBuilder(metadata, name, constantNamesAndOffsets, this,
+            charOffset, charEndOffset),
         charOffset);
   }
 
   void addFunctionTypeAlias(
       List<MetadataBuilder> metadata,
       KernelTypeBuilder returnType,
       String name,
       List<TypeVariableBuilder> typeVariables,
       List<FormalParameterBuilder> formals,
       int charOffset) {
@@ skipping 161 matching lines @@
   }
 }
 
 bool isConstructorName(String name, String className) {
   if (name.startsWith(className)) {
     if (name.length == className.length) return true;
     if (name.startsWith(".", className.length)) return true;
   }
   return false;
 }