NetworkProcess crashes in WebCoreResourceHandleAsOperationQueueDelegate callbacks.
<rdar://problem/13541868> and https://bugs.webkit.org/show_bug.cgi?id=113664

Reviewed by Dan Bernstein.

In the "two-part" callbacks that involve waiting on a semaphore for the async block to finish,
the delegate might have been destroyed by the time the wait completes.

A RetainPtr<> protector will fix that up nicely.

* platform/network/mac/WebCoreResourceHandleAsOperationQueueDelegate.mm:
(-[WebCoreResourceHandleAsOperationQueueDelegate connection:willSendRequest:redirectResponse:]):
(-[WebCoreResourceHandleAsOperationQueueDelegate connectionShouldUseCredentialStorage:]):
(-[WebCoreResourceHandleAsOperationQueueDelegate connection:canAuthenticateAgainstProtectionSpace:]):
(-[WebCoreResourceHandleAsOperationQueueDelegate connection:willCacheResponse:]):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@147287 268f45cc-cd09-0410-ab3c-d52691b4dbfc