The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/3dad54187991ac8ca25e8bd3116f110b1319e8df

commit 3dad54187991ac8ca25e8bd3116f110b1319e8df
Author: lanwei <lanwei@chromium.org>
Date: Tue Nov 29 22:26:45 2016

Keep the old TimeToFirstScrollUpdateSwapBegin2 metrics until M56 is stable.

We should keep the old touch's and wheel's TimeToFirstScrollUpdateSwapBegin2 metrics
with the new ones until new metrics is at stable, so we can keep the data continuous.

BUG= 669618 

Review-Url: https://codereview.chromium.org/2533223004
Cr-Commit-Position: refs/heads/master@{#435094}

[modify] https://crrev.com/3dad54187991ac8ca25e8bd3116f110b1319e8df/content/browser/renderer_host/input/render_widget_host_latency_tracker.cc
[modify] https://crrev.com/3dad54187991ac8ca25e8bd3116f110b1319e8df/tools/metrics/histograms/histograms.xml

lanwei@ can we remove this metric now? M56 has gone stable a while ago...

Yes, I will have patch to remove it soon.

This is fixed now right?

No. This is a different metric from what I removed. I'll remove this one too.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/e743dce5f0b60adeb73c21bdc4457a79d090217a

commit e743dce5f0b60adeb73c21bdc4457a79d090217a
Author: Navid Zolghadr <nzolghadr@chromium.org>
Date: Tue Oct 24 14:24:01 2017

Remove remaining old input scroll metrics

Remove
*.ScrollUpdate.*.TimeToFirstScrollUpdateSwapBegin2
metrics that were replaces by
*.ScrollBegin.*.TimeToScrollUpdateSwapBegin2.

Bug:  669618 
Change-Id: I26332fedfdeb7091208c65adfcea735c3c59ffbf
Reviewed-on: https://chromium-review.googlesource.com/733781
Reviewed-by: Timothy Dresser <tdresser@chromium.org>
Reviewed-by: Steven Holte <holte@chromium.org>
Commit-Queue: Navid Zolghadr <nzolghadr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#511137}
[modify] https://crrev.com/e743dce5f0b60adeb73c21bdc4457a79d090217a/tools/metrics/histograms/histograms.xml
[modify] https://crrev.com/e743dce5f0b60adeb73c21bdc4457a79d090217a/ui/latency/latency_tracker.cc

Now it should be all done.