Implement the function.sent proposal.

src/parsing/parser-base.h

Index: src/parsing/parser-base.h
diff --git a/src/parsing/parser-base.h b/src/parsing/parser-base.h
index e4947f208a2fa631dae8d5202ebd722ad8486d86..8077a05a638a4e0557e65a10a3b2e418e5d9658f 100644
--- a/src/parsing/parser-base.h
+++ b/src/parsing/parser-base.h
@@ -2544,6 +2544,24 @@ ParserBase<Traits>::ParseMemberExpression(ExpressionClassifier* classifier,
 
     Consume(Token::FUNCTION);
     int function_token_position = position();
+
+    if (FLAG_harmony_function_sent && Check(Token::PERIOD)) {
+      // function.sent
+
+      int pos = position();
+      ExpectContextualKeyword(CStrVector("sent"), CHECK_OK);
+
+      if (!is_generator()) {
+        // TODO(neis): allow escaping into closures?
+        ReportMessageAt(scanner()->location(),
+                        MessageTemplate::kUnexpectedFunctionSent);
+        *ok = false;
+        return this->EmptyExpression();
+      }
+
+      return this->FunctionSentExpression(scope_, factory(), pos);
+    }
+
     bool is_generator = Check(Token::MUL);
     IdentifierT name = this->EmptyIdentifier();
     bool is_strict_reserved_name = false;