Revert "Parts must start with 'part of'" and "Attempt to fix VM build"

dart/samples/ui_lib/layout/GridLayoutParser.dart

-part of layout;
-
 // Copyright (c) 2011, 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.
 
 /**
  * Base class for simple recursive descent parsers.
  * Handles the lower level stuff, i.e. what a scanner/tokenizer would do.
  */
 class _Parser {
   static const WHITESPACE = ' \r\n\t';
@@ skipping 466 matching lines @@
   String toString() {
     String location;
     if (_offset < _source.length) {
       location = 'location: ${_source.substring(_offset)}';
     } else {
       location = 'end of input';
     }
     return 'SyntaxErrorException: $_message at $location';
   }
 }