REGRESSION (r182866): repeated prompts for password on internal Apple website using...

REGRESSION (r182866): repeated prompts for password on internal Apple website using workers
https://bugs.webkit.org/show_bug.cgi?id=146769

Reviewed by Sam Weinig.

Not sure how to make a regression test for this. Sure would be nice to have one though.

* loader/ThreadableLoader.cpp:
(WebCore::ThreadableLoaderOptions::ThreadableLoaderOptions): Added. Calls through to the
base class copy constructor to copy data members of the base class (the lack of this was
the bug). Also initializes all the data members of this class.
(WebCore::ThreadableLoaderOptions::isolatedCopy): Changed to call the constructor above.

* loader/ThreadableLoader.h: Added new constructor.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@186592 268f45cc-cd09-0410-ab3c-d52691b4dbfc