https://chat.google.com
Reactivation Score: -0.4893	
Site Engagement Score: 	1.8
Cannot discard due to blacklist.

https://calendar.google.com
Reactivation Score: -0.1996
Site Engagement Score: 	2.3	
Cannot discard due to blacklist.

Yeah, the site engagement scores are below the threshold :/

I suppose there are 2 rough ways to address this:

(1) Give scores a liner boost based on background feature usage; we can guarantee they are above the threshold, but not guarantee they will be loaded as there may be may other much more important sites that load first before we deem we have run out of resources.
(2) Make them absolutely the most important, after visible tabs. Ensures they are the next thing loaded.

Thoughts?

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/ec8f8e9de867c3eec0a27b16af92255ac82643c6

commit ec8f8e9de867c3eec0a27b16af92255ac82643c6
Author: Chris Hamilton <chrisha@chromium.org>
Date: Wed Dec 19 15:14:23 2018

Add callback to local site DB when data is loaded.

This will be used by the session restore machinery to wait for information regarding background feature usage.

BUG=915714

Change-Id: I68e09f56484595596ef84fbb486ace8878d4352c
Reviewed-on: https://chromium-review.googlesource.com/c/1380803
Commit-Queue: Chris Hamilton <chrisha@chromium.org>
Reviewed-by: François Doray <fdoray@chromium.org>
Cr-Commit-Position: refs/heads/master@{#617835}
[modify] https://crrev.com/ec8f8e9de867c3eec0a27b16af92255ac82643c6/chrome/browser/resource_coordinator/local_site_characteristics_data_impl.cc
[modify] https://crrev.com/ec8f8e9de867c3eec0a27b16af92255ac82643c6/chrome/browser/resource_coordinator/local_site_characteristics_data_impl.h
[modify] https://crrev.com/ec8f8e9de867c3eec0a27b16af92255ac82643c6/chrome/browser/resource_coordinator/local_site_characteristics_data_impl_unittest.cc
[modify] https://crrev.com/ec8f8e9de867c3eec0a27b16af92255ac82643c6/chrome/browser/resource_coordinator/local_site_characteristics_data_reader.cc
[modify] https://crrev.com/ec8f8e9de867c3eec0a27b16af92255ac82643c6/chrome/browser/resource_coordinator/local_site_characteristics_data_reader.h
[modify] https://crrev.com/ec8f8e9de867c3eec0a27b16af92255ac82643c6/chrome/browser/resource_coordinator/site_characteristics_data_reader.h

This issue has an owner, a component and a priority, but is still listed as untriaged or unconfirmed. By definition, this bug is triaged. Changing status to "assigned". Please reach out to me if you disagree with how I've done this.