The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/a3b17964413c5c6630917b8238d6f9681d6bca9e

commit a3b17964413c5c6630917b8238d6f9681d6bca9e
Author: tdresser <tdresser@chromium.org>
Date: Mon Mar 27 22:01:08 2017

Record the fraction of the time without user input - Aura only.

We don't have a good sense of how long Chrome sits idle, without any
input. Gather this via UMA.

I'll plumb up the FractionOfTimeWithoutUserInputRecorder on other platforms in subsequent patches.

BUG= 702198 

Review-Url: https://codereview.chromium.org/2751403002
Cr-Commit-Position: refs/heads/master@{#459897}

[modify] https://crrev.com/a3b17964413c5c6630917b8238d6f9681d6bca9e/tools/metrics/histograms/histograms.xml
[modify] https://crrev.com/a3b17964413c5c6630917b8238d6f9681d6bca9e/ui/aura/window_event_dispatcher.cc
[modify] https://crrev.com/a3b17964413c5c6630917b8238d6f9681d6bca9e/ui/aura/window_event_dispatcher.h
[modify] https://crrev.com/a3b17964413c5c6630917b8238d6f9681d6bca9e/ui/aura/window_event_dispatcher_unittest.cc
[modify] https://crrev.com/a3b17964413c5c6630917b8238d6f9681d6bca9e/ui/events/BUILD.gn
[add] https://crrev.com/a3b17964413c5c6630917b8238d6f9681d6bca9e/ui/events/fraction_of_time_without_user_input_recorder.cc
[add] https://crrev.com/a3b17964413c5c6630917b8238d6f9681d6bca9e/ui/events/fraction_of_time_without_user_input_recorder.h
[add] https://crrev.com/a3b17964413c5c6630917b8238d6f9681d6bca9e/ui/events/fraction_of_time_without_user_input_recorder_unittest.cc