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This CL adds a histogram that tracks the difference in input event
timestamp based on TimeTicks::Now and timestamp reported via
PerformanceCount. It will help analyze the distribution of how far
negative or positive TimeTicks::Now is compared to PerformanceCount.
This will help guide a decision on what timestamp to use in the future
for velocity calculation, input prediction, and gesture recognition.

For additional context, please see discussion at input-dev
https://groups.google.com/a/chromium.org/forum/#!topic/input-dev/KZMZ6dnzKZQ

Change-Id: I20dfee67b0ff959edcb0a81c551675f61b2549a6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1666298
Commit-Queue: Sarthak Shah <sarsha@microsoft.com>
Reviewed-by: David Bokan <bokan@chromium.org>
Reviewed-by: Robert Liao <robliao@chromium.org>
Reviewed-by: Ilya Sherman <isherman@chromium.org>
Reviewed-by: Navid Zolghadr <nzolghadr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#680244}