This test sets a cookie, then follows a link with a ping attribute where the ping URL matches a 'block-cookie' rule.   

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Frame: 'link_frame'
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Link with ping was clicked.

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Frame: 'result_frame'
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Ping received.
HTTP_HOST: 127.0.0.1:8000
REQUEST_URI: /contentextensions/resources/save-ping.php?test=contentextensions-block-cookies-in-ping
No cookies in ping.