Persist PWA plus install icon across page loads within the app scope

This CL ensures we remember if a site is within a previously seen
installable scope and avoid flashing the PWA install icon redundantly.

Navigations between different installable scopes will still refresh
the PWA install icon and animation.


Bug: 907351
Change-Id: Ib21542d44fafb7d6777b6782ba1654266d2e582f
Commit-Queue: Dominick Ng <>
Reviewed-by: Dominick Ng <>
Auto-Submit: Alan Cutter <>
Cr-Commit-Position: refs/heads/master@{#642935}
11 files changed