fix fasta scanner adapter lineStarts

pkg/analyzer/test/generated/scanner_test.dart

 // Copyright (c) 2014, 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 analyzer.test.generated.scanner_test;
 
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/src/dart/ast/token.dart';
 import 'package:analyzer/src/dart/scanner/reader.dart';
 import 'package:analyzer/src/dart/scanner/scanner.dart';
@@ skipping 105 matching lines @@
   }
 
   void test_lineInfo_slashN() {
     String source = "class Test {\n}";
     _assertLineInfo(source, [
       new ScannerTest_ExpectedLocation(0, 1, 1),
       new ScannerTest_ExpectedLocation(source.indexOf("}"), 2, 1)
     ]);
   }
 
+  void test_linestarts() {
+    String source = "var\r\ni\n=\n1;\n";
+    GatheringErrorListener listener = new GatheringErrorListener();
+    Scanner scanner =
+        new Scanner(null, new CharSequenceReader(source), listener);
+    var token = scanner.tokenize();
+    expect(token.lexeme, 'var');
+    var lineStarts = scanner.lineStarts;
+    expect(lineStarts, orderedEquals([0, 5, 7, 9, 12]));
+  }
+
   void _assertLineInfo(
       String source, List<ScannerTest_ExpectedLocation> expectedLocations) {
     GatheringErrorListener listener = new GatheringErrorListener();
     _scanWithListener(source, listener);
     listener.assertNoErrors();
     LineInfo info = listener.getLineInfo(new TestSource());
     expect(info, isNotNull);
     int count = expectedLocations.length;
     for (int i = 0; i < count; i++) {
       ScannerTest_ExpectedLocation expectedLocation = expectedLocations[i];
@@ skipping 91 matching lines @@
     buffer.write(token.type);
     buffer.write(", '");
     buffer.write(token.lexeme);
     buffer.write("', ");
     buffer.write(token.offset);
     buffer.write(", ");
     buffer.write(token.length);
     buffer.write("]");
   }
 }