Fixed <rdar://problem/4052683> After adding/removing stocks from Stocks Widget,...

	Fixed <rdar://problem/4052683> After adding/removing stocks from Stocks Widget, stock areas went blank

	The request was being collected before firing it's load handler.
	We now gc protect the request while it's loading.

        Reviewed by Maciej.

        * khtml/ecma/xmlhttprequest.cpp:
        (KJS::XMLHttpRequest::send):
        (KJS::XMLHttpRequest::abort):
        (KJS::XMLHttpRequest::slotFinished):
        (KJS::XMLHttpRequestProtoFunc::tryCall):

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@8973 268f45cc-cd09-0410-ab3c-d52691b4dbfc