[generators] Desugar yield*.

src/parsing/preparser.h

Index: src/parsing/preparser.h
diff --git a/src/parsing/preparser.h b/src/parsing/preparser.h
index 976fa7cfe7dbaf39600f605e9b01d9f538082502..5d4df475d82ce5f5f162094192cf8c19d48e42ec 100644
--- a/src/parsing/preparser.h
+++ b/src/parsing/preparser.h
@@ -946,6 +946,9 @@ class PreParserTraits {
       PreParserExpression property, const ExpressionClassifier* classifier,
       bool* ok);
 
+  inline PreParserExpression RewriteYieldStar(
+      PreParserExpression generator, PreParserExpression expr, int pos);
+
  private:
   PreParser* pre_parser_;
 };
@@ -1143,6 +1146,13 @@ PreParserExpression PreParserTraits::RewriteNonPatternObjectLiteralProperty(
 }
 
 
+PreParserExpression PreParserTraits::RewriteYieldStar(
+    PreParserExpression generator, PreParserExpression expression, int pos) {
+  return pre_parser_->factory()->NewYield(
+      generator, expression, Yield::kDelegating, pos);
+}
+
+
 PreParserStatementList PreParser::ParseEagerFunctionBody(
     PreParserIdentifier function_name, int pos,
     const PreParserFormalParameters& parameters, FunctionKind kind,