<rdar://problem/4993055> auto_refcount_underflow_error: WebCore::FrameLoader::continueAfterNavigationPolicy () over-releases under GC

        Add ::adoptNS and ::adoptCF methods to RetainPtr to indicate what type of reference to adopt.
        
        * platform/cf/RetainPtr.h:
        (WebCore::):
        (WebCore::adoptNSReference):
        (WebCore::RetainPtr::RetainPtr):
        (WebCore::::adoptCF):
        (WebCore::::adoptNS):
        * platform/mac/FileChooserMac.mm:
        (WebCore::FileChooser::FileChooser):
        * platform/network/mac/ResourceErrorMac.mm:
        (WebCore::ResourceError::operator NSError*):
        * platform/network/mac/ResourceRequestMac.mm:
        (WebCore::ResourceRequest::doUpdatePlatformRequest):
        * platform/network/mac/ResourceResponseMac.mm:
        (WebCore::ResourceResponse::nsURLResponse):



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@19660 268f45cc-cd09-0410-ab3c-d52691b4dbfc