hanxi@chromium.org xinyiji@chromium.org

Records whether the last active tab is a NewTabPage during tab restore in cold startup when Start surface is showing. The histogram is logged in deferred startup tasks.

hanxi@chromium.org xinyiji@chromium.org

Record the total count of clicks on different modules of the Start surface page. For most visited tiles: is recorded when 1) user clicks on most visited tiles; 2) long press on most visited tiles to open in a new tab or a new incognito tab or to download the link. This is consistent with MobileNTPMostVisited. For feeds: is recorded when 1) user clicks on feeds; 2) long press on feeds to open in a new tab or open in a new incognito tab or check about this source and topic; 3) click the learn more button on the top of the feeds section. For omnibox: is recorded every time when user uses Omnibox or voice search on Omnibox to navigate. This is consistent with MobileOmniboxUse. For single tab card: is recorded every time when user clicks on the single tab card. For tab switcher button: is recorded every time when user clicks on the tab switcher button. For profile button: is recorded when user clicks on the profile button. For menu button: is recorded when user clicks on the menu button. The histogram is logged on Start surface and is Android-only.

hanxi@chromium.org xinyiji@chromium.org

Records the StartSurfaceState when Start surface or Grid tab switcher is showing due to ChromeTabbedActivity#showOverview() is called. It includes showing at cold or warm startup, or when users bringing Chrome from background to foreground, or via back operations from a Tab etc. The histogram doesn't include the cases of showing overview page due to the transition between Start surface and Tab switcher.

sreejakshetty@chromium.org hanxi@chromium.org

Records the time between showing the start surface and starting the spare tab creation. It does not include the time spent creating the spare tab. Every time a spare tab is created for the start surface, this is recorded.

hanxi@chromium.org xinyiji@chromium.org

The time spent on the start surface as measured from when it was loaded or last brought to the foreground until it was navigated away from or hidden. Only measured on Android.