The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/472ae5bd891b7b6b73555ac8f9af8c61814cb3b9

commit 472ae5bd891b7b6b73555ac8f9af8c61814cb3b9
Author: Alexei Svitkine <asvitkine@chromium.org>
Date: Tue Aug 29 19:40:20 2017

Delete obsolete Android type id logging code.

It was originally added here:
https://codereview.chromium.org/137623002

It was later refactored as part of the metrics provider
interface introduction:
https://codereview.chromium.org/294043008

However, it was never hooked up properly so no data was logged.

Later, since the histograms were never logged, they were
marked as obsolete by this CL:
https://codereview.chromium.org/1934723002

However, checking my local state file, it seems there still
is a need to clean up the prefs, because the list ones are
still there (and empty), so added some code for that.

BUG= 758719 

Change-Id: Ic098104f902c786403bca14d76a05fae8b96eef5
Reviewed-on: https://chromium-review.googlesource.com/633689
Commit-Queue: Alexei Svitkine (very slow) <asvitkine@chromium.org>
Reviewed-by: Bernhard Bauer <bauerb@chromium.org>
Reviewed-by: Ilya Sherman <isherman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#498204}
[modify] https://crrev.com/472ae5bd891b7b6b73555ac8f9af8c61814cb3b9/chrome/android/BUILD.gn
[modify] https://crrev.com/472ae5bd891b7b6b73555ac8f9af8c61814cb3b9/chrome/browser/BUILD.gn
[delete] https://crrev.com/abbfa348d9f8a3ce2185f4ee678b86b08cf52d4c/chrome/browser/android/activity_type_ids.cc
[delete] https://crrev.com/abbfa348d9f8a3ce2185f4ee678b86b08cf52d4c/chrome/browser/android/activity_type_ids.h
[modify] https://crrev.com/472ae5bd891b7b6b73555ac8f9af8c61814cb3b9/chrome/browser/metrics/android_metrics_provider.cc
[modify] https://crrev.com/472ae5bd891b7b6b73555ac8f9af8c61814cb3b9/chrome/browser/metrics/android_metrics_provider.h
[modify] https://crrev.com/472ae5bd891b7b6b73555ac8f9af8c61814cb3b9/chrome/browser/metrics/chrome_metrics_service_client.cc
[modify] https://crrev.com/472ae5bd891b7b6b73555ac8f9af8c61814cb3b9/chrome/browser/prefs/browser_prefs.cc
[modify] https://crrev.com/472ae5bd891b7b6b73555ac8f9af8c61814cb3b9/chrome/common/pref_names.cc
[modify] https://crrev.com/472ae5bd891b7b6b73555ac8f9af8c61814cb3b9/chrome/common/pref_names.h