Reviewed by Andreas Kling.

        Remove empty class CallbackGuard
        https://bugs.webkit.org/show_bug.cgi?id=60610

        CallbackGuard was only ever used on Tiger and it is now an empty class. Remove all uses of it.

        * platform/network/mac/ResourceHandleMac.mm:
        (-[WebCoreResourceHandleAsDelegate connection:willSendRequest:redirectResponse:]):
        (-[WebCoreResourceHandleAsDelegate connectionShouldUseCredentialStorage:]):
        (-[WebCoreResourceHandleAsDelegate connection:didReceiveAuthenticationChallenge:]):
        (-[WebCoreResourceHandleAsDelegate connection:didCancelAuthenticationChallenge:]):
        (-[WebCoreResourceHandleAsDelegate connection:canAuthenticateAgainstProtectionSpace:]):
        (-[WebCoreResourceHandleAsDelegate connection:didReceiveResponse:]):
        (-[WebCoreResourceHandleAsDelegate connection:didReceiveData:lengthReceived:]):
        (-[WebCoreResourceHandleAsDelegate connection:willStopBufferingData:]):
        (-[WebCoreResourceHandleAsDelegate connection:didSendBodyData:totalBytesWritten:totalBytesExpectedToWrite:]):
        (-[WebCoreResourceHandleAsDelegate connectionDidFinishLoading:]):
        (-[WebCoreResourceHandleAsDelegate connection:didFailWithError:]):
        (-[WebCoreResourceHandleAsDelegate connection:willCacheResponse:]):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@86309 268f45cc-cd09-0410-ab3c-d52691b4dbfc