Changes

* [https://telemetry.mozilla.org/new-pipeline/dist.html#!cumulative=0&end_date=2016-04-25&keys=__none__!__none__!__none__&max_channel_version=aurora%252F47&measure=TRACKING_PROTECTION_ENABLED&min_channel_version=null&product=Firefox&sanitize=1&sort_keys=submissions&start_date=2016-03-08&table=1&trim=1&use_submission_date=0 TRACKING_PROTECTION_ENABLED]: sessions with tracking protection true if a session has <tt>privacy.trackingprotection.enabled globally</tt> '''turned on'''* [https://telemetry.mozilla.org/new-pipeline/dist.html#!cumulative=0&end_date=2016-04-25&keys=__none__!__none__!__none__&max_channel_version=aurora%252F47&measure=TRACKING_PROTECTION_EVENTS&min_channel_version=null&product=Firefox&sanitize=1&sort_keys=submissions&start_date=2016-03-08&table=1&trim=1&use_submission_date=0 TRACKING_PROTECTION_EVENTS]: 0 = security state changed, 1 = user clicked the button to disable TP on the current page, 2 = user clicked to re-enable TP on the page* [https://telemetry.mozilla.org/new-pipeline/dist.html#!cumulative=0&end_date=2016-04-25&keys=__none__!__none__!__none__&max_channel_version=aurora%252F47&measure=TRACKING_PROTECTION_PBM_DISABLED&min_channel_version=null&product=Firefox&sanitize=1&sort_keys=submissions&start_date=2016-03-08&table=1&trim=1&use_submission_date=0 TRACKING_PROTECTION_PBM_DISABLED]: whether or not tracking protection in private browsing mode is disabledtrue if a session has <tt>privacy.trackingprotection.pbmode.enabled</tt> '''turned off'''* [https://telemetry.mozilla.org/new-pipeline/dist.html#!cumulative=0&end_date=2016-06-05&keys=__none__!__none__!__none__&max_channel_version=nightly%252F49&measure=TRACKING_PROTECTION_SHIELD&min_channel_version=null&product=Firefox&sanitize=1&sort_keys=submissions&start_date=2016-04-24&table=1&trim=1&use_submission_date=0 TRACKING_PROTECTION_SHIELD]: whether for each pageload, 0 if the shield is not shown (no trackers), 1 if the shield is crossed-out or not(page is whitelisted) and 2 if the shield is shown normally (trackers blocked) on a page load Notes:* no telemetry pings are sent while in Private Browsing mode* we only have telemetry when TP is enabled in the session