M-55 or M-56? 

The CL is done. I just need one last lgtm from histograms.xml folks in the US.
https://codereview.chromium.org/2395123002/
I hope to land it in a couple of hours.

I am not sure if the BP already happened. If so, it is a political decision whether M55 or M56...

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/b5893c0d4748c70ae1eb140d17ba188ce6e1e842

commit b5893c0d4748c70ae1eb140d17ba188ce6e1e842
Author: jkrcal <jkrcal@chromium.org>
Date: Mon Oct 10 11:16:44 2016

Connecting UserClassifier to NtpSnippetsFetcher

This CL applies UserClassifier in NtpSnippetsFetcher. The application is
twofold:
 - current user class is sent in each request to content suggestion
   server,
 - RequestThrottler for NtpSnippetsFetcher is notified of current class
   and thus can apply different quota for different user classes.

To make this possible, this CL add to RequestThrottler support for
changing RequestType on the fly.

The CL also fixes a typo from CL 2400133002: "top_languages" -> "topLanguages".

BUG=651813, 653526 

Review-Url: https://codereview.chromium.org/2395123002
Cr-Commit-Position: refs/heads/master@{#424132}

[modify] https://crrev.com/b5893c0d4748c70ae1eb140d17ba188ce6e1e842/chrome/browser/ntp_snippets/content_suggestions_service_factory.cc
[modify] https://crrev.com/b5893c0d4748c70ae1eb140d17ba188ce6e1e842/components/ntp_snippets/remote/ntp_snippets_fetcher.cc
[modify] https://crrev.com/b5893c0d4748c70ae1eb140d17ba188ce6e1e842/components/ntp_snippets/remote/ntp_snippets_fetcher.h
[modify] https://crrev.com/b5893c0d4748c70ae1eb140d17ba188ce6e1e842/components/ntp_snippets/remote/ntp_snippets_fetcher_unittest.cc
[modify] https://crrev.com/b5893c0d4748c70ae1eb140d17ba188ce6e1e842/components/ntp_snippets/remote/ntp_snippets_service_unittest.cc
[modify] https://crrev.com/b5893c0d4748c70ae1eb140d17ba188ce6e1e842/components/ntp_snippets/remote/request_throttler.cc
[modify] https://crrev.com/b5893c0d4748c70ae1eb140d17ba188ce6e1e842/components/ntp_snippets/remote/request_throttler.h
[modify] https://crrev.com/b5893c0d4748c70ae1eb140d17ba188ce6e1e842/components/ntp_snippets/remote/request_throttler_unittest.cc
[modify] https://crrev.com/b5893c0d4748c70ae1eb140d17ba188ce6e1e842/components/ntp_snippets/user_classifier.cc
[modify] https://crrev.com/b5893c0d4748c70ae1eb140d17ba188ce6e1e842/ios/chrome/browser/ntp_snippets/ios_chrome_content_suggestions_service_factory.cc
[modify] https://crrev.com/b5893c0d4748c70ae1eb140d17ba188ce6e1e842/tools/metrics/histograms/histograms.xml

Forgot to close the bug back then.