Reviewed by Darin.

        Fix for http://bugs.webkit.org/show_bug.cgi?id=10190
        REGRESSION: Repro crash when navigating away from an image document that hasn't finished loading

        No test case added (probably requires new DumpRenderTree functionality)

        * rendering/RenderImage.cpp:
        (WebCore::RenderImage::imageChanged): Added early return if the document is
        being destroyed.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@16697 268f45cc-cd09-0410-ab3c-d52691b4dbfc