- restored some code I removed in the Range change; this code can't go
          until the rest of the Range fix is in

        * dom/Range.cpp:
        (WebCore::Range::commonAncestorContainer): Added back the check for 0
        that I removed erroneously in the Range patch.
        (WebCore::Range::processContents): Left in assertions I used to debug
        this.

LayoutTests:

        Reviewed by Beth Dakin.

        Update test to catch the SECURITY_ERR thrown by
        CanvasRenderingContext2D::getImageData() and
        HTMLCanvasElement::toDataURL() on a tainted canvas

        * http/tests/security/canvas-remote-read-remote-image-expected.txt:
        * http/tests/security/canvas-remote-read-remote-image.html:



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@30979 268f45cc-cd09-0410-ab3c-d52691b4dbfc