[es6] Implement spec compliant ToPrimitive in the runtime.

src/objects-inl.h

Index: src/objects-inl.h
diff --git a/src/objects-inl.h b/src/objects-inl.h
index 57750c3459187f53f3bf43bda562d0bf3baeeaac..a37fcd58369c83a7fcb4be93efa62cd8eb658656 100644
--- a/src/objects-inl.h
+++ b/src/objects-inl.h
@@ -1132,6 +1132,7 @@ bool Object::FitsRepresentation(Representation representation) {
 }
 
 
+// static
 MaybeHandle<JSReceiver> Object::ToObject(Isolate* isolate,
                                          Handle<Object> object) {
   return ToObject(
@@ -1139,6 +1140,21 @@ MaybeHandle<JSReceiver> Object::ToObject(Isolate* isolate,
 }
 
 
+// static
+MaybeHandle<Name> Object::ToName(Isolate* isolate, Handle<Object> input) {
+  if (input->IsName()) return Handle<Name>::cast(input);
+  return ToString(isolate, input);
+}
+
+
+// static
+MaybeHandle<Object> Object::ToPrimitive(Handle<Object> input,
+                                        ToPrimitiveHint hint) {
+  if (input->IsPrimitive()) return input;
+  return JSReceiver::ToPrimitive(Handle<JSReceiver>::cast(input), hint);
+}
+
+
 bool Object::HasSpecificClassOf(String* name) {
   return this->IsJSObject() && (JSObject::cast(this)->class_name() == name);
 }