https://bugs.webkit.org/show_bug.cgi?id=112970

        Reviewed by Brady Eidson.

        WebCore clients do not need explicit control over what queue ResourceHandle works on,
        they just want to avoid blocking main thread.

        * platform/network/ResourceHandleClient.h:
        (WebCore::ResourceHandleClient::usesAsyncCallbacks): Added. The name doesn't quite
        match what ResourceHandleMac currently does, but it will very soon.

        * platform/network/NetworkingContext.h:
        (WebCore::NetworkingContext::scheduledRunLoopPairs):
        * platform/network/mac/ResourceHandleMac.mm:
        (WebCore::operationQueueForAsyncClients):
        (WebCore::ResourceHandle::start):



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@146536 268f45cc-cd09-0410-ab3c-d52691b4dbfc