+talo

To get a more holistic view of this, any chance we could measure this on startup of Chrome for example, instead of only when people in fact clear the data?

That way we could more easily reason about whether we should point users to the Manage Space activity more often or not.

Unfortunately that will be quite a lot of disk access on startup - that's the one downside here, we don't actually have easy numbers here without doing a lot of disk activity. In a better state of our quota system, we could probably have this number pretty easily, but for now we have to do file operations which is slow.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/0b12ba0411a8c50fd8e51aeb6510cf1465ef13b5

commit 0b12ba0411a8c50fd8e51aeb6510cf1465ef13b5
Author: Daniel Murphy <dmurph@chromium.org>
Date: Fri Oct 12 22:23:57 2018

[ManageSpace] Record histogram of user's web storage size

Bug:  875439 
Change-Id: If6c56a4c634ce685a4e1ab93660ae95db7d90716
Reviewed-on: https://chromium-review.googlesource.com/c/1274599
Reviewed-by: Mark Pearson <mpearson@chromium.org>
Reviewed-by: Theresa <twellington@chromium.org>
Commit-Queue: Daniel Murphy <dmurph@chromium.org>
Cr-Commit-Position: refs/heads/master@{#599380}
[modify] https://crrev.com/0b12ba0411a8c50fd8e51aeb6510cf1465ef13b5/chrome/android/java/src/org/chromium/chrome/browser/preferences/website/ManageSpaceActivity.java
[modify] https://crrev.com/0b12ba0411a8c50fd8e51aeb6510cf1465ef13b5/tools/metrics/histograms/histograms.xml

metrics strings:
Android.ManageSpace.TotalDiskUsageMB
Android.ManageSpace.UnimportantDiskUsageMB

Current histograms (from canary):
https://uma.googleplex.com/p/chrome/histograms/?endDate=20181028&dayCount=7&histograms=Android.ManageSpace.TotalDiskUsageMB%2CAndroid.ManageSpace.UnimportantDiskUsageMB&fixupData=true&showMax=true&filters=platform%2Ceq%2CA%2Cisofficial%2Ceq%2CTrue&implicitFilters=isofficial