Weifagn - re: file type, do you mean Crostini, Arc, etc.? Or do you mean extension?

If you mean extension, we'd need to have an enum listing all the enums you care about as we can't just log the actual file extension. We can only list which one of a configured list of file extensions it is.

Oh ignore #3, just saw we must already have this somewhere.

We already have FileBrowser.Viewing[File|Task|Root]Type, I'll add ....Online and ....Offline versions of these as well.

is that what you had in mind?

Yes, thanks!

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/6325a876f34e5702402e95e0bbf21706a1b21794

commit 6325a876f34e5702402e95e0bbf21706a1b21794
Author: Ben Wells <benwells@chromium.org>
Date: Fri Nov 23 05:24:46 2018

Add online / offline version of two FileManager metrics.

The two metrics are FileManager.ViewingFileType and
Filemanager.ViewingRootType.

Bug:  846132 
No-try: true
Change-Id: Iecafeabbeaa100495762af1d492c73cd23d9d6ac
Reviewed-on: https://chromium-review.googlesource.com/c/1345949
Reviewed-by: Noel Gordon <noel@chromium.org>
Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Reviewed-by: Sam McNally <sammc@chromium.org>
Commit-Queue: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#610539}
[modify] https://crrev.com/6325a876f34e5702402e95e0bbf21706a1b21794/tools/metrics/histograms/histograms.xml
[modify] https://crrev.com/6325a876f34e5702402e95e0bbf21706a1b21794/ui/file_manager/file_manager/foreground/js/file_tasks.js

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/fd01f2dc231149e2943eadf58506382776d6f65c

commit fd01f2dc231149e2943eadf58506382776d6f65c
Author: Ben Wells <benwells@chromium.org>
Date: Fri Nov 23 07:50:35 2018

Add online and offline version of FileBrowser.ViewingTaskType metric.

Bug:  846132 
Change-Id: I69820a9934ad73810a8c67e20d53cddffb045ded
Reviewed-on: https://chromium-review.googlesource.com/c/1345684
Commit-Queue: Sam McNally <sammc@chromium.org>
Reviewed-by: Sam McNally <sammc@chromium.org>
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Cr-Commit-Position: refs/heads/master@{#610547}
[modify] https://crrev.com/fd01f2dc231149e2943eadf58506382776d6f65c/chrome/browser/chromeos/file_manager/file_tasks.cc
[modify] https://crrev.com/fd01f2dc231149e2943eadf58506382776d6f65c/tools/metrics/histograms/histograms.xml