Handle 'part of' declarations with URI correctly in Fasta.

pkg/front_end/lib/src/fasta/parser/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.
 
 library fasta.parser.parser;
 
 import '../scanner.dart' show ErrorToken;
 
 import '../scanner/recover.dart' show closeBraceFor, skipToEof;
 
@@ skipping 330 matching lines @@
     listener.endPart(partKeyword, semicolon);
     return token;
   }
 
   Token parsePartOf(Token token) {
     listener.beginPartOf(token);
     assert(optional('part', token));
     assert(optional('of', token.next));
     Token partKeyword = token;
     token = token.next.next;
-    if (token.isIdentifier()) {
+    bool hasName = token.isIdentifier();
+    if (hasName) {
       token = parseQualified(token, IdentifierContext.partName,
           IdentifierContext.partNameContinuation);
     } else {
       token = parseLiteralStringOrRecoverExpression(token);
     }
     Token semicolon = token;
     token = expect(';', token);
-    listener.endPartOf(partKeyword, semicolon);
+    listener.endPartOf(partKeyword, semicolon, hasName);
     return token;
   }
 
   Token parseMetadataStar(Token token, {bool forParameter: false}) {
     listener.beginMetadataStar(token);
     int count = 0;
     while (optional('@', token)) {
       token = parseMetadata(token);
       count++;
     }
@@ skipping 3227 matching lines @@
         break;
     }
     if (isRecoverable) {
       listener.handleRecoverableError(token, kind, arguments);
       return null;
     } else {
       return listener.handleUnrecoverableError(token, kind, arguments);
     }
   }
 }