Tracking bug to implement metrics (probably user actions) for the user menu. See more background here: https://groups.google.com/a/google.com/forum/#!topic/chrome-signin/Tj32-x_ua3Q

Copying a list of metrics I proposed in that thread:
(1) User menu is opened
(2) Passwords/Payments/Addresses is clicked from autofill home
(3) A list of profiles is displayed (i.e. the user menu was opened & there was more than one profile, so we showed the list of profiles)
(4) A profile is clicked from the list of profiles to switch to another profile
(5) "Open Guest Window" is clicked
(6) "Manage People" is clicked
(7) "Exit <person>"/"Close all your windows" is clicked
(8) "Sign in again" button is displayed (i.e. the user menu was opened & the user was in a "sync paused" state)
(9) "Sign in again" button is clicked when the user is in a "sync paused" state

(3) and (8) would be used as a denominator to calculate the CTR for profile switching/"Sign in again."