The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/5d3b45405c2293919755229ee1741c969482afcf

commit 5d3b45405c2293919755229ee1741c969482afcf
Author: Mounir Lamouri <mlamouri@chromium.org>
Date: Wed Nov 01 17:16:19 2017

Media Engagement: record metrics related to data clearing.

This is adding a user action metric that records when site data are
cleared and a histogram that record the reduction in MEI score when
history is cleared.

Bug:  778701 
Change-Id: Iec07a068a9230b15b8fa52aeed00ab9ef573dfe2
Reviewed-on: https://chromium-review.googlesource.com/739389
Commit-Queue: Mounir Lamouri <mlamouri@chromium.org>
Reviewed-by: Ilya Sherman <isherman@chromium.org>
Reviewed-by: Bernhard Bauer <bauerb@chromium.org>
Reviewed-by: Becca Hughes <beccahughes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#513162}
[modify] https://crrev.com/5d3b45405c2293919755229ee1741c969482afcf/chrome/android/javatests/src/org/chromium/chrome/browser/preferences/privacy/BrowsingDataBridgeTest.java
[modify] https://crrev.com/5d3b45405c2293919755229ee1741c969482afcf/chrome/browser/browsing_data/chrome_browsing_data_remover_delegate.cc
[modify] https://crrev.com/5d3b45405c2293919755229ee1741c969482afcf/chrome/browser/media/media_engagement_service.cc
[modify] https://crrev.com/5d3b45405c2293919755229ee1741c969482afcf/chrome/browser/media/media_engagement_service.h
[modify] https://crrev.com/5d3b45405c2293919755229ee1741c969482afcf/chrome/browser/media/media_engagement_service_unittest.cc
[modify] https://crrev.com/5d3b45405c2293919755229ee1741c969482afcf/tools/metrics/actions/actions.xml
[modify] https://crrev.com/5d3b45405c2293919755229ee1741c969482afcf/tools/metrics/histograms/histograms.xml