Record 'implements' keyword for class declaration nodes.

lib/compiler/implementation/scanner/parser.dart

 // Copyright (c) 2012, 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.
 
 /**
  * An event generating parser of Dart programs. This parser expects
  * all tokens in a linked list (aka a token stream).
  *
  * The class [Scanner] is used to generate a token stream. See the
  * file scanner.dart.
@@ skipping 212 matching lines @@
     if (optional('extends', token)) {
       extendsKeyword = token;
       token = parseType(token.next);
     } else {
       extendsKeyword = null;
       listener.handleNoType(token);
     }
     Token implementsKeyword;
     int interfacesCount = 0;
     if (optional('implements', token)) {
+      implementsKeyword = token;
       do {
         token = parseType(token.next);
         ++interfacesCount;
       } while (optional(',', token));
     }
     token = parseClassBody(token);
     listener.endClassDeclaration(interfacesCount, begin, extendsKeyword,
                                  implementsKeyword, token);
     return token.next;
   }
@@ skipping 1471 matching lines @@
     }
     listener.handleContinueStatement(hasTarget, continueKeyword, token);
     return expectSemicolon(token);
   }
 
   Token parseEmptyStatement(Token token) {
     listener.handleEmptyStatement(token);
     return expectSemicolon(token);
   }
 }