[Android] Enable session invalidations while the RecentTabsPage is open
The "AndroidSessionNotifications" experiment disables session invalidations
because session sync invalidations represent the bulk of the invalidation
traffic. Session invalidations cause the client to fetch the updated
"Recent Tabs" from the sync server.
This CL enables session sync invalidations only after the user has had the
RecentTabsPage open for a while. This enables the Android RecentTabsPage to be
"live": If a user opens a tab on a device which is signed in to the same profile
as the Android device, the RecentTabsPage on the Android device is updated with
the new tab. The CL disables session sync when the RecentTabsPage is closed
because the invalidations are not longer useful at that time.
BUG=477054
TEST=InvalidationControllerTest.*
Review URL: https://codereview.chromium.org/
1263773007
Cr-Commit-Position: refs/heads/master@{#342363}