ValueSerializer: Handle JS_SPECIAL_API_OBJECT_TYPE.

src/value-serializer.cc

Index: src/value-serializer.cc
diff --git a/src/value-serializer.cc b/src/value-serializer.cc
index b0ecc6ddd5f1d10916fd4225ddf1873e68aeb210..ac8de6383d6cd12abc5e00798a0e60d242f9effb 100644
--- a/src/value-serializer.cc
+++ b/src/value-serializer.cc
@@ -349,7 +349,8 @@ Maybe<bool> ValueSerializer::WriteJSReceiver(Handle<JSReceiver> receiver) {
 
   // Eliminate callable and exotic objects, which should not be serialized.
   InstanceType instance_type = receiver->map()->instance_type();
-  if (receiver->IsCallable() || instance_type <= LAST_SPECIAL_RECEIVER_TYPE) {
+  if (receiver->IsCallable() || (instance_type <= LAST_SPECIAL_RECEIVER_TYPE &&
+                                 instance_type != JS_SPECIAL_API_OBJECT_TYPE)) {
     ThrowDataCloneError(MessageTemplate::kDataCloneError, receiver);
     return Nothing<bool>();
   }
@@ -362,8 +363,11 @@ Maybe<bool> ValueSerializer::WriteJSReceiver(Handle<JSReceiver> receiver) {
     case JS_ARRAY_TYPE:
       return WriteJSArray(Handle<JSArray>::cast(receiver));
     case JS_OBJECT_TYPE:
-    case JS_API_OBJECT_TYPE: {
+    case JS_API_OBJECT_TYPE:
+    case JS_SPECIAL_API_OBJECT_TYPE: {
       Handle<JSObject> js_object = Handle<JSObject>::cast(receiver);
+      if (instance_type == JS_SPECIAL_API_OBJECT_TYPE)
+        DCHECK(js_object->GetInternalFieldCount());

[Jakob Kummerow, 2016/09/23 17:20:30]

nit: {} please

Or even better:

DCHECK_IMPLIES(instance_type == JS_SPECIAL_API_OBJECT_TYPE,
               js_object->GetInternalFieldCount());

Or even better:

case JS_SPECIAL_API_OBJECT_TYPE:
  return WriteHostObject(Handle<JSObject>::cast(receiver));

[jbroman, 2016/09/23 17:50:36]

Urgh. I've been writing Blink CLs mostly for the last week or two. Sorry.
Oh, v8 still has DCHECK_IMPLIES? Neat. It was removed from Chromium.
Done.

       return js_object->GetInternalFieldCount() ? WriteHostObject(js_object)
                                                 : WriteJSObject(js_object);
     }