Use packages dart_parser, dart_scanner, and compiler_util.

pkg/compiler/lib/src/serialization/system.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 dart2js.serialization_system;
 
 import 'dart:async';
 
 import '../common.dart';
 import '../common/resolution.dart';
 import '../compiler.dart';
 import '../elements/resolution_types.dart';
 import '../elements/elements.dart';
-import '../scanner/scanner.dart';
 import '../script.dart';
 import '../serialization/impact_serialization.dart';
-import '../tokens/token.dart';
+import 'package:dart_scanner/dart_scanner.dart';
 import '../universe/call_structure.dart';
 import '../universe/use.dart';
 import '../universe/world_impact.dart';
 import 'modelz.dart';
 import 'resolved_ast_serialization.dart';
 import 'serialization.dart';
 import 'task.dart';
 
 class ResolutionDeserializerSystem extends DeserializerSystem {
   final Compiler _compiler;
@@ skipping 280 matching lines @@
   }
 
   Token findToken(Uri uri, int offset) {
     Token beginToken = beginTokenMap.putIfAbsent(uri, () {
       Script script = scripts[uri];
       if (script == null) {
         parsingContext.reporter.internalError(NO_LOCATION_SPANNABLE,
             'No source file found for $uri in:\n ${scripts.keys.join('\n ')}');
       }
       if (script.isSynthesized) return null;
-      return new Scanner(script.file).tokenize();
+      return parsingContext.scanner.scanFile(script.file);
     });
     if (beginToken == null) return null;
     return ResolvedAstDeserializer.findTokenInStream(beginToken, offset);
   }
 
   @override
   void onElement(Element element, ObjectDecoder getDecoder(String tag)) {
     ObjectDecoder decoder = getDecoder(RESOLVED_AST_TAG);
     if (decoder != null) {
       _decoderMap[element] = decoder;
     }
   }
 }