Add ProfileMetricsRecorder

...to track and record profile related usage metrics during runtime.
Metrics are recorded per profile, i.e. each profile is assigned an ID
which corresponds to a histogram bucket.

The histogram Profile.BrowserActive.PerProfile is added.

(cherry picked from commit c67ace4a61ef46140193228317a636e7ce19d35c)

Bug: 965469
Change-Id: I2012eb8f3ec1a7ed6ddb54f703453d8d559d0f23
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1625117
Reviewed-by: Mihai Sardarescu <msarda@chromium.org>
Reviewed-by: Robert Kaplow (slow) <rkaplow@chromium.org>
Reviewed-by: Marc Treib <treib@chromium.org>
Commit-Queue: Thomas Tangl <tangltom@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#667281}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1655788
Reviewed-by: Thomas Tangl <tangltom@chromium.org>
Cr-Commit-Position: refs/branch-heads/3809@{#249}
Cr-Branched-From: d82dec1a818f378c464ba307ddd9c92133eac355-refs/heads/master@{#665002}

• chrome/browser/BUILD.gn[diff]
• chrome/browser/chrome_browser_main.cc[diff]
• chrome/browser/prefs/browser_prefs.cc[diff]
• chrome/browser/profiles/profile_activity_metrics_recorder.cc[Added - diff]
• chrome/browser/profiles/profile_activity_metrics_recorder.h[Added - diff]
• chrome/browser/profiles/profile_activity_metrics_recorder_unittest.cc[Added - diff]
• chrome/browser/profiles/profile_attributes_entry.cc[diff]
• chrome/browser/profiles/profile_attributes_entry.h[diff]
• chrome/test/BUILD.gn[diff]
• tools/metrics/histograms/histograms.xml[diff]