I would see problems where the QNetworkReply would be deleted in the other thread, but a new QNetworkReply would be allocated by the heap at the same address and would break the comparison code path.
Another problem would be that didFinishLoading would eventually call abort on the ResourceHandle, which would call deleteLater on the reply (if in a different thread). Calling deleteLater on oldReply would then cause a crash.
Created attachment 76061 [details]
Comment on attachment 76061 [details]
Rejecting patch 76061 from commit-queue.
Failed to run "['./WebKitTools/Scripts/webkit-patch', '--status-host=queues.webkit.org', '--bot-id=eseidel-sf', 'apply-attachment', '--force-clean', '--non-interactive', 76061]" exit_code: 2
Last 500 characters of output:
'Kenneth Rohde Christiansen', u'--force']" exit_code: 1
Parsed 2 diffs from patch file(s).
patching file WebCore/ChangeLog
Hunk #1 succeeded at 1 with fuzz 3.
patching file WebCore/platform/network/qt/QNetworkReplyHandler.cpp
Hunk #1 FAILED at 300.
1 out of 1 hunk FAILED -- saving rejects to file WebCore/platform/network/qt/QNetworkReplyHandler.cpp.rej
Failed to run "[u'/Projects/CommitQueue/WebKitTools/Scripts/svn-apply', u'--reviewer', u'Kenneth Rohde Christiansen', u'--force']" exit_code: 1
Full output: http://queues.webkit.org/results/6943017
Committed r73708: <http://trac.webkit.org/changeset/73708>
http://trac.webkit.org/changeset/73708 might have broken GTK Linux 32-bit Debug