I think it's not, and should be removed. I'll take a stab at it, unless someone else gets to it first :)

This might be a nice opportunity to revisit the various states a category can have.
I think we can simplify this a lot. Speaking of which there are probably other signals we send to the UI which can be revisited -- some also have a little complicated semantics. Would be a shame to re-implement things in iOS which aren't needed anymore. 

Should we book some time tomorrow or next week to look into these?

Yup, that SGTM. We also need to include Android UI folks, since they'll know better which information is actually needed.

Independent of that, I'll see about removing that status, which should be an easy cleanup.

Indeed, we don't use it anymore.

The last thing we did with it was use it as a signal to clear the suggestions on sign out, but this has been replaced by an explicit onFullRefreshRequired() method on the bridge in https://codereview.chromium.org/2519053002. The current code that mentions it can't be reached.

So removing SIGNED_OUT is fine from a UI perspective

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/ce0e63223261f496b2721a83c42aae8b163da960

commit ce0e63223261f496b2721a83c42aae8b163da960
Author: treib <treib@chromium.org>
Date: Fri Mar 10 16:11:52 2017

Cleanup: Remove CategoryStatus::SIGNED_OUT

BUG=699979

Review-Url: https://codereview.chromium.org/2740783004
Cr-Commit-Position: refs/heads/master@{#456073}

[modify] https://crrev.com/ce0e63223261f496b2721a83c42aae8b163da960/chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/SectionList.java
[modify] https://crrev.com/ce0e63223261f496b2721a83c42aae8b163da960/chrome/android/java/src/org/chromium/chrome/browser/ntp/snippets/SnippetsBridge.java
[modify] https://crrev.com/ce0e63223261f496b2721a83c42aae8b163da960/chrome/android/junit/src/org/chromium/chrome/browser/ntp/cards/NewTabPageAdapterTest.java
[modify] https://crrev.com/ce0e63223261f496b2721a83c42aae8b163da960/chrome/android/junit/src/org/chromium/chrome/browser/ntp/cards/SuggestionsSectionTest.java
[modify] https://crrev.com/ce0e63223261f496b2721a83c42aae8b163da960/chrome/browser/android/ntp/content_suggestions_notifier_service.cc
[modify] https://crrev.com/ce0e63223261f496b2721a83c42aae8b163da960/chrome/browser/ntp_snippets/download_suggestions_provider_unittest.cc
[modify] https://crrev.com/ce0e63223261f496b2721a83c42aae8b163da960/chrome/browser/ui/webui/snippets_internals_message_handler.cc
[modify] https://crrev.com/ce0e63223261f496b2721a83c42aae8b163da960/chrome/test/android/javatests/src/org/chromium/chrome/test/util/browser/suggestions/FakeSuggestionsSource.java
[modify] https://crrev.com/ce0e63223261f496b2721a83c42aae8b163da960/components/ntp_snippets/category_status.h

Repurposing the bug for cleaning up the CategoryStatus values we send to the UI:

The UI mostly cares about a bool that says whether the category is there or not. In addition, it uses the INITIALIZING and AVAILABLE_LOADING states as a signal that it should show a loading indicator.

Note: the UI does not use AVAILABLE_LOADING and INITIALIZING as the only signals for showing the loading indicator. Triggering a "fetch more" action also shows the indicator until the associated callback is triggered, without the above statuses being involved.

Throwing back into the pool, since I'm not actively working on this.

This issue has been Available for over a year. If it's no longer important or seems unlikely to be fixed, please consider closing it out. If it is important, please re-triage the issue.

Sorry for the inconvenience if the bug really should have been left as Available.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

jkrcal: Is something going to happen here? I don't want to assign to treib@ based on comment 9.

Not on our end (treib@, jkrcal@). We do not own the ntp_snippets component any more.

cc'ing zea@ to possibly re-triage.

Filip, could you take a look (and possibly close out)?