RFR (S) 8250589: Move Universe::_reference_pending_list into OopHandle

[Kim Barrett]

> On Jul 27, 2020, at 1:28 PM, coleen.phillimore at oracle.com wrote:
> 
> 
> 
> On 7/27/20 1:08 PM, Kim Barrett wrote:
>>> On Jul 27, 2020, at 10:10 AM, coleen.phillimore at oracle.com wrote:
>>> On 7/27/20 9:21 AM, Aleksey Shipilev wrote:
>>>> On 7/27/20 3:05 PM, coleen.phillimore at oracle.com wrote:
>>>> *) The change below implicitly tests for NULL now? Seems like _reference_pending_list.peek() would
>>>> be more efficient here, as it would not ask GC to keep the oop alive (especially when it is
>>>> guaranteed to be already alive, right?).
>>>> 
>>>>  bool Universe::has_reference_pending_list() {
>>>>    assert_pll_ownership();
>>>> -  return _reference_pending_list != NULL;
>>>> +  return _reference_pending_list.resolve();
>>>>  }
>>>> 
>>> This can be peek().  I'll change it.
>> HotSpot Style Guide says not to use implicit conversions to bool.
>> The “!= NULL” was intentional and should be retained.
>> 
> Yes, thanks for catching that.
> Coleen

Change is good with that fixed and the changes Aleksey suggested.