fix debug checks for api callbacks returning symbols

test/cctest/test-api.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 23630 matching lines @@
       "  for (var i = 0; i < 5; i++) {\n"
       "    x(1,2,3);\n"
       "  }\n"
       "}\n"
       "x_wrap();\n"
       "%OptimizeFunctionOnNextCall(x_wrap);"
       "x_wrap();\n");
 }
 
 
+static void ReturnsSymbolCallback(
+    const v8::FunctionCallbackInfo<v8::Value>& info) {
+  info.GetReturnValue().Set(v8::Symbol::New(info.GetIsolate()));
+}
+
+
+TEST(ApiCallbackCanReturnSymbols) {
+  i::FLAG_allow_natives_syntax = true;
+  LocalContext context;
+  v8::Isolate* isolate = context->GetIsolate();
+  v8::HandleScope scope(isolate);
+  Handle<Object> global = context->Global();
+  Local<v8::Function> function = Function::New(isolate, ReturnsSymbolCallback);
+  global->Set(v8_str("x"), function);
+  CompileRun(
+      "function x_wrap() {\n"
+      "  for (var i = 0; i < 5; i++) {\n"
+      "    x();\n"
+      "  }\n"
+      "}\n"
+      "x_wrap();\n"
+      "%OptimizeFunctionOnNextCall(x_wrap);"
+      "x_wrap();\n");
+}
+
+
 static const char* last_event_message;
 static int last_event_status;
 void StoringEventLoggerCallback(const char* message, int status) {
     last_event_message = message;
     last_event_status = status;
 }
 
 
 TEST(EventLogging) {
   v8::Isolate* isolate = CcTest::isolate();
@@ skipping 1075 matching lines @@
                    "bar2.js");
 }
 
 
 TEST(StreamingScriptWithSourceMappingURLInTheMiddle) {
   const char* chunks[] = {"function foo() { ret", "urn 13; }\n//#",
                           " sourceMappingURL=bar2.js\n", "foo();", NULL};
   RunStreamingTest(chunks, v8::ScriptCompiler::StreamedSource::UTF8, true, NULL,
                    "bar2.js");
 }