Importable profiles should have additional fields set

[garrettr]

Updated issue description by @bsclifton

Having access to a few additional fields would let us present a better import experience. For example, the profiles could be grouped by browser, sorted by last used, and the icons associated with each profile could be displayed.

Profile level fields in Local State file

For Chromium profiles, in GetChromeSourceProfiles (common/importer/chrome_importer_utils.cc) we can get the last used time (in epoch format) for each profile. It's stored in the Local State file under the profile with the field active_time. The active profile icon (which would be useful when presenting the profile in the UI) is there under avatar_icon (and the URL will load fine in Brave).

Browser level fields

If the profiles that are importable are grouped by browser, there are some additional fields we could set. For example, last_active_profiles lets us know the last used profile for that browser. It would be useful to know if the browser is the default browser for the OS. Default browser isn't something stored in the file but is something we can test for.

Original issue description

Chrome orders the list of browser profiles that are available for import such that the default browser's profiles appear first in the list. This is convenient because most users are likely to want to import their current browser's settings, and their current browser is probably also the default.

Since Chrome only supports importing from Firefox or the OS's default browser (Safari/Edge/etc.), it is enough to check whether Firefox is the user's default browser or not. Since we've added the option to import Chrome/Chromium/Chrome Canary profiles, we should also check whether Chrome is the default browser and build/sort the list of profiles accordingly.