[Fasta] Include line starts

pkg/front_end/lib/src/fasta/source/source_loader.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_loader;
 
 import 'dart:async' show Future;
 
 import 'dart:io' show FileSystemException;
 
@@ skipping 45 matching lines @@
       return inputError(library.uri, -1, "Not found: ${library.uri}.");
     }
     try {
       List<int> bytes = sourceBytes[uri];
       if (bytes == null) {
         bytes = sourceBytes[uri] = await readBytesFromFile(uri);
       }
       byteCount += bytes.length - 1;
       ScannerResult result = scan(bytes);
       Token token = result.tokens;
-      if (!suppressLexicalErrors) {
-        target.addLineStarts(library.fileUri, result.lineStarts);
-      }
+      target.addLineStarts(library.fileUri, result.lineStarts);

[ahe, 2017/03/03 09:03:58]

Are you sure this is necessary?

       while (token is ErrorToken) {
         if (!suppressLexicalErrors) {
           ErrorToken error = token;
           printUnexpected(uri, token.charOffset, error.assertionMessage);
         }
         token = token.next;
       }
       return token;
     } on FileSystemException catch (e) {
       String message = e.message;
@@ skipping 258 matching lines @@
 
   void computeHierarchy(Program program) {
     hierarchy = new ClassHierarchy(program);
     ticker.logMs("Computed class hierarchy");
     coreTypes = new CoreTypes(program);
     ticker.logMs("Computed core types");
   }
 
   List<Uri> getDependencies() => sourceBytes.keys.toList();
 }