Following up on a suggestion by Alex Christensen in bug 162520, comment 11, we should use a polling approach instead of a hardcoded timeout in the following tests: LayoutTests/http/tests/contentextensions/hide-on-ping-with-ping-that-redirects.html LayoutTests/http/tests/navigation/ping-attribute/anchor-ping-and-do-not-follow-redirect-when-sending-ping.html LayoutTests/http/tests/security/contentSecurityPolicy/report-blocked-uri-and-do-not-follow-redirect-when-sending-report.php LayoutTests/http/tests/security/xssAuditor/report-script-tag-and-do-not-follow-redirect-when-sending-report.html LayoutTests/http/tests/security/xssAuditor/report-script-tag-full-block-and-do-not-follow-redirect-when-sending-report.html Although the polling approach may not necessarily allow us to remove an upper bound hardcoded timeout, it will allow a test to complete before the upper bound timeout.