Reviewed by Geoff and Justin.

    Reviewed by Geoff and Justin.

        Fix for <rdar://problem/5246941> Clicking URL field on
        Safari causes halt for a minute when using input methods.
        and <rdar://problem/5245964> Safari hangs for several
        seconds when trying to select text using mouse

        This is a by product of the textStorage hack used to fix
        rdar://problem/5000470 -- TSM calls textStorage repeatedly
        when changing focus, on certain mouse events, etc.  If there
        is no selection/editable region we repeatedly create an
        NSAttributedString from the full document.  If the document is
        sufficiently long this starts consuming an inordinate amount of
        time.

        This check should really have been present in the original
        patch.

        * WebKit.xcodeproj/project.pbxproj:
        * WebView/WebHTMLView.mm:
        (-[WebHTMLView textStorage]):

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@21976 268f45cc-cd09-0410-ab3c-d52691b4dbfc