Merge 139038

Merge 139038
> REGRESSION(r137406): Text inside an empty optgroup prevents subsequent options from appearing
> https://bugs.webkit.org/show_bug.cgi?id=106298
> 
> Reviewed by Ryosuke Niwa.
> 
> Source/WebCore:
> 
> Test: fast/forms/select/select-empty-optgroup.html
> 
> * html/HTMLSelectElement.cpp:
> (WebCore::HTMLSelectElement::recalcListItems):
> Traverse to the first element within the 'current' only if it exists.
> 
> LayoutTests:
> 
> * fast/forms/select/select-empty-optgroup-expected.html: Added.
> * fast/forms/select/select-empty-optgroup.html: Added.
> 

TBR=tkent@chromium.org
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=139721