[BlackBerry] NetworkJob can access deleted objects.

[BlackBerry] NetworkJob can access deleted objects.
https://bugs.webkit.org/show_bug.cgi?id=79246

Patch by Yong Li <yoli@rim.com> on 2012-02-22
Reviewed by Antonio Gomes.

When a NetworkJob is created by unload handler, we still need
to send the request to the server, but we shouldn't save and
keep using the Frame pointer because the frame is being detached.
The NetworkJob will be cancelled by PingLoader as soon as it gets
first response from host.
Also see https://bugs.webkit.org/show_bug.cgi?id=30457.

No new tests because existing test case is good enough like
LayoutTests/http/tests/navigation/image-load-in-unload-handler.html.

* platform/network/blackberry/NetworkJob.cpp:
(WebCore::NetworkJob::NetworkJob):
(WebCore::NetworkJob::initialize):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@108601 268f45cc-cd09-0410-ab3c-d52691b4dbfc