Implement character offsets for fields and enum constants.

pkg/front_end/lib/src/fasta/source/source_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.source_library_builder;
 
 import 'package:kernel/ast.dart' show AsyncMarker, ProcedureKind;
 
 import '../combinator.dart' show Combinator;
 
@@ skipping 166 matching lines @@
       List<TypeVariableBuilder> typeVariables,
       int modifiers,
       T mixinApplication,
       List<T> interfaces,
       int charOffset);
 
   void addField(List<MetadataBuilder> metadata, int modifiers, T type,
       String name, int charOffset);
 
   void addFields(List<MetadataBuilder> metadata, int modifiers, T type,
-      List<String> names) {
-    for (String name in names) {
-      // TODO(ahe): Get charOffset of name.
-      addField(metadata, modifiers, type, name, -1);
+      List<Object> namesAndOffsets) {
+    for (int i = 0; i < namesAndOffsets.length; i += 2) {
+      String name = namesAndOffsets[i];
+      int charOffset = namesAndOffsets[i + 1];
+      addField(metadata, modifiers, type, name, charOffset);
     }
   }
 
   void addProcedure(
       List<MetadataBuilder> metadata,
       int modifiers,
       T returnType,
       String name,
       List<TypeVariableBuilder> typeVariables,
       List<FormalParameterBuilder> formals,
       AsyncMarker asyncModifier,
       ProcedureKind kind,
       int charOffset,
       int charOpenParenOffset,
       int charEndOffset,
       String nativeMethodName,
       {bool isTopLevel});
 
   void addEnum(List<MetadataBuilder> metadata, String name,
-      List<String> constants, int charOffset, int charEndOffset);
+      List<Object> constantNamesAndOffsets, int charOffset, int charEndOffset);
 
   void addFunctionTypeAlias(
       List<MetadataBuilder> metadata,
       T returnType,
       String name,
       List<TypeVariableBuilder> typeVariables,
       List<FormalParameterBuilder> formals,
       int charOffset);
 
   FunctionTypeBuilder addFunctionType(
@@ skipping 304 matching lines @@
   }
 
   /// Called to register [procedure] as a factory whose types are collected in
   /// [factoryDeclaration]. Later, once the class has been built, we can
   /// synthesize type variables on the factory matching the class'.
   void addFactoryDeclaration(
       ProcedureBuilder procedure, DeclarationBuilder<T> factoryDeclaration) {
     factoryDeclarations[procedure] = factoryDeclaration;
   }
 }