chromium/chrome/test/data/extensions/api_test/printing_metrics/update_manifest.xml

<?xml version='1.0' encoding='UTF-8'?>
<!--
  This update manifest points to the printing_metrics.crx file.
  "mock.http" is a placeholder that gets substituted with the test server
  address in runtime.
-->
<gupdate xmlns='http://www.google.com/update2/response' protocol='2.0'>
  <app appid='cmgkkmeeoiceijkpmaabbmpgnkpaaela'>
    <updatecheck
        codebase='http://mock.http/extensions/api_test/printing_metrics.crx'
        version='0.1' />
   </app>
</gupdate>