Reviewed by Dan Bernstein.

        Fix for <rdar://problem/7014389> REGRESSION(4-TOT): Hyperlinks have no tooltips in Mail unless you first click in the message body

        Updated these new methods (added as part of the viewless WebKit effort) that call through to WebHTMLView to use _selectedOrMainFrame, 
        instead of just selectedFrame.  When the selection changes, I don't think there is a situation where there's no selected frame, but
        it seems better to keep these two uses the same, since if there is a case, this will be more like the old behavior, before there was
        a version of _selectionChanged in WebView. 

        * WebView/WebView.mm:
        (-[WebView _setToolTip:]):
        (-[WebView _selectionChanged]):



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@45427 268f45cc-cd09-0410-ab3c-d52691b4dbfc