[GTK] Fix platformDefersLoading to handle non-http requests, and

[GTK] Fix platformDefersLoading to handle non-http requests, and
to not use broken-ish libsoup APIs.
https://bugs.webkit.org/show_bug.cgi?id=72227

Patch by Dan Winship <danw@gnome.org> on 2011-11-16
Reviewed by Martin Robinson.

* platform/network/ResourceHandleInternal.h:
* platform/network/soup/ResourceHandleSoup.cpp:
(WebCore::sendRequestCallback):
(WebCore::startHTTPRequest):
(WebCore::hasBeenSent):
(WebCore::ResourceHandle::platformSetDefersLoading):
(WebCore::readCallback): rather than deferring by using
soup_session_pause_message(), let the read complete, but just don't
process the result until we're no longer deferred.
(WebCore::startNonHTTPRequest): Don't start the request if
it's deferred.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@100466 268f45cc-cd09-0410-ab3c-d52691b4dbfc