Remove timeStamp from the ChangeBuilder API

pkg/analyzer_plugin/lib/src/utilities/change_builder/change_builder_dart.dart

 // Copyright (c) 2017, 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.
 
 import 'dart:async';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
@@ skipping 22 matching lines @@
    * The analysis driver in which the files being edited were analyzed.
    */
   final AnalysisDriver driver;
 
   /**
    * Initialize a newly created change builder.
    */
   DartChangeBuilderImpl(this.driver);
 
   @override
-  Future<Null> addFileEdit(String path, int fileStamp,
-          void buildFileEdit(DartFileEditBuilder builder)) =>
-      super.addFileEdit(path, fileStamp, buildFileEdit);
+  Future<Null> addFileEdit(
+          String path, void buildFileEdit(DartFileEditBuilder builder)) =>
+      super.addFileEdit(path, buildFileEdit);
 
   @override
-  Future<DartFileEditBuilderImpl> createFileEditBuilder(
-      String path, int fileStamp) async {
+  Future<DartFileEditBuilderImpl> createFileEditBuilder(String path) async {
     AnalysisResult result = await driver.getResult(path);
-    return new DartFileEditBuilderImpl(this, path, fileStamp, result.unit);
+    int timeStamp = driver.fsState.getFileForPath(path).exists ? 0 : -1;
+    return new DartFileEditBuilderImpl(this, path, timeStamp, result.unit);
   }
 }
 
 /**
  * An [EditBuilder] used to build edits in Dart files.
  */
 class DartEditBuilderImpl extends EditBuilderImpl implements DartEditBuilder {
   List<String> _KNOWN_METHOD_NAME_PREFIXES = ['get', 'is', 'to'];
 
   /**
@@ skipping 1339 matching lines @@
   }
 }
 
 class _InsertionDescription {
   final int offset;
   final bool insertEmptyLineBefore;
   final bool insertEmptyLineAfter;
   _InsertionDescription(
       this.offset, this.insertEmptyLineBefore, this.insertEmptyLineAfter);
 }