Allow sync *, async * and yield * in dart2js

pkg/compiler/lib/src/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.
 
 part of scanner;
 
 class FormalParameterType {
   final String type;
   const FormalParameterType(this.type);
   bool get isRequired => this == REQUIRED;
@@ skipping 1494 matching lines @@
     token = token.next;
     while (notEofOrValue('}', token)) {
       token = parseStatement(token);
       ++statementCount;
     }
     listener.endFunctionBody(statementCount, begin, token);
     expect('}', token);
     return token;
   }
 
-  /// `async*` and `sync*` are parsed a two tokens, [token] and [star]. This
-  /// method checks that there is no whitespace between [token] and [star].
-  void checkStarredModifier(Token token, Token star, String name) {
-    if (star.charOffset > token.charOffset + token.charCount) {
-      listener.reportError(new TokenPair(token, star),
-          MessageKind.INVALID_STARRED_KEYWORD, {'keyword': name});
-    }
-  }
-
   Token parseAsyncModifier(Token token) {
     Token async;
     Token star;
     awaitIsKeyword = false;
     yieldIsKeyword = false;
     if (optional('async', token)) {
       awaitIsKeyword = true;
       async = token;
       token = token.next;
       if (optional('*', token)) {
         yieldIsKeyword = true;
         star = token;
         token = token.next;
-        checkStarredModifier(async, star, 'async*');
       }
     } else if (optional('sync', token)) {
       async = token;
       token = token.next;
       if (optional('*', token)) {
         yieldIsKeyword = true;
         star = token;
         token = token.next;
-
-        checkStarredModifier(async, star, 'sync*');
       } else {
         listener.reportError(async,
             MessageKind.INVALID_SYNC_MODIFIER);
       }
     }
     listener.handleAsyncModifier(async, star);
     return token;
   }
 
   Token parseStatement(Token token) {
@@ skipping 52 matching lines @@
 
   Token parseYieldStatement(Token token) {
     Token begin = token;
     listener.beginYieldStatement(begin);
     assert(identical('yield', token.stringValue));
     token = token.next;
     Token starToken;
     if (optional('*', token)) {
       starToken = token;
       token = token.next;
-      checkStarredModifier(begin, starToken, 'yield*');
     }
     token = parseExpression(token);
     listener.endYieldStatement(begin, starToken, token);
     return expectSemicolon(token);
   }
 
 
   Token parseReturnStatement(Token token) {
     Token begin = token;
     listener.beginReturnStatement(begin);
@@ skipping 1043 matching lines @@
     }
     listener.handleContinueStatement(hasTarget, continueKeyword, token);
     return expectSemicolon(token);
   }
 
   Token parseEmptyStatement(Token token) {
     listener.handleEmptyStatement(token);
     return expectSemicolon(token);
   }
 }