Update ObjectToString to Harmony-draft algorithm

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 13471 matching lines @@
   CHECK(value->IsString() && value->Equals(v8_str("[object MyClass]")));
 
   // Check global
   value = context->Global()->ObjectProtoToString();
   CHECK(value->IsString() && value->Equals(v8_str("[object global]")));
 
   // Check ordinary object
   Local<Value> object = v8_compile("new Object()")->Run();
   value = object.As<v8::Object>()->ObjectProtoToString();
   CHECK(value->IsString() && value->Equals(v8_str("[object Object]")));
+
+  // Check that ES6 semantics using @@toStringTag work
+  i::FLAG_harmony_tostring = true;
+  Local<v8::Symbol> toStringTag = v8::Symbol::GetToStringTag(isolate);
+
+  object = v8_compile("new Object()")->Run();
+  object.As<v8::Object>()->Set(toStringTag, v8_str("Foo"));
+  value = object.As<v8::Object>()->ObjectProtoToString();
+  CHECK(value->IsString() && value->Equals(v8_str("[object Foo]")));
+
+  object = v8_compile("new Object()")->Run();
+  object.As<v8::Object>()->Set(toStringTag, v8_str("Array"));
+  value = object.As<v8::Object>()->ObjectProtoToString();
+  CHECK(value->IsString() && value->Equals(v8_str("[object ~Array]")));

[Dmitry Lomov (no reviews), 2014/10/18 15:16:48]

Add a test that creates an object with a getter for toStringTag. Actually two:
one that completes normally and one that throws. 

Add tests for all cases from 19.1.3.6.

 }
 
 
 THREADED_TEST(ObjectGetConstructorName) {
   LocalContext context;
   v8::HandleScope scope(context->GetIsolate());
   v8_compile("function Parent() {};"
              "function Child() {};"
              "Child.prototype = new Parent();"
              "var outer = { inner: function() { } };"
@@ skipping 10332 matching lines @@
   char chunk2[] =
       "XXr = 13;\n"
       "  return foob\xeb\x91\x80\xeb\x91\x80r;\n"
       "}\n";
   chunk1[strlen(chunk1) - 1] = reference[0];
   chunk2[0] = reference[1];
   chunk2[1] = reference[2];
   const char* chunks[] = {chunk1, chunk2, "foo();", NULL};
   RunStreamingTest(chunks, v8::ScriptCompiler::StreamedSource::UTF8);
 }