Reviewed by Maciej.

    Reviewed by Maciej.

        - fix two recently introduced leaks: one of an NSString, the other of a WebDataSource

        * Loader/WebDocumentLoadState.m: (-[WebDocumentLoadState setTitle:]):
        Rearranged code to avoid storage leak in case of identical title.

        * Loader/WebFrameLoader.h: Removed _setPolicyDocumentLoadState: method
        from the header.
        * Loader/WebFrameLoader.m:
        (-[WebFrameLoader _setPolicyDocumentLoadState:]): Added logic to call detachFromFrameLoader
        as needed if this load state is going away rather than moving on to become the provisional
        load state.
        (-[WebFrameLoader shouldReloadToHandleUnreachableURLFromRequest:]): Tweaked formatting.
        (-[WebFrameLoader _loadRequest:archive:]): Added an assertion.
        (-[WebFrameLoader _loadRequest:triggeringAction:loadType:formState:]): Added an assertion.
        (-[WebFrameLoader _reloadAllowingStaleDataWithOverrideEncoding:]): Added an assertion.
        (-[WebFrameLoader reload]): Added an assertion.
        (-[WebFrameLoader loadDataSource:withLoadType:formState:]): Added a local variable to avoid
        calling _documentLoadState over and over again.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@16887 268f45cc-cd09-0410-ab3c-d52691b4dbfc