The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/3fddfc508938ba41dbaacebb204cbf45e6e99b83

commit 3fddfc508938ba41dbaacebb204cbf45e6e99b83
Author: nzolghadr <nzolghadr@chromium.org>
Date: Tue Dec 13 21:52:12 2016

Add TimeToScrollUpdateSwapBegin2 in RAPPOR

Add first rappor metric in content for input.
The metric uses the same data as the existing
UMA metric:

Event.Latency.ScrollUpdate.Touch.
TimeToScrollUpdateSwapBegin2

adding the domain information on top.

BUG= 663471 

Review-Url: https://codereview.chromium.org/2492793004
Cr-Commit-Position: refs/heads/master@{#438297}

[modify] https://crrev.com/3fddfc508938ba41dbaacebb204cbf45e6e99b83/components/rappor/test_rappor_service.cc
[modify] https://crrev.com/3fddfc508938ba41dbaacebb204cbf45e6e99b83/components/rappor/test_rappor_service.h
[modify] https://crrev.com/3fddfc508938ba41dbaacebb204cbf45e6e99b83/content/browser/renderer_host/DEPS
[modify] https://crrev.com/3fddfc508938ba41dbaacebb204cbf45e6e99b83/content/browser/renderer_host/input/render_widget_host_latency_tracker.cc
[modify] https://crrev.com/3fddfc508938ba41dbaacebb204cbf45e6e99b83/content/browser/renderer_host/input/render_widget_host_latency_tracker.h
[modify] https://crrev.com/3fddfc508938ba41dbaacebb204cbf45e6e99b83/content/browser/renderer_host/input/render_widget_host_latency_tracker_unittest.cc
[modify] https://crrev.com/3fddfc508938ba41dbaacebb204cbf45e6e99b83/content/browser/renderer_host/render_widget_host_impl.cc
[modify] https://crrev.com/3fddfc508938ba41dbaacebb204cbf45e6e99b83/content/test/BUILD.gn
[modify] https://crrev.com/3fddfc508938ba41dbaacebb204cbf45e6e99b83/tools/metrics/rappor/rappor.xml