GitLab

Adds --gamepad-polling-interval [INTERVAL], where INTERVAL is the delay
in milliseconds between successive polls of gamepad button and axis
inputs. Decreasing the interval improves latency, but may cause a loss
in performance due to more CPU time spent in the input polling thread.
The interval must be between 4 and 16 ms, inclusive. If no interval is
specified the max value (16ms) is used.

Also adds chrome://flags#gamepad-polling-rate to allow selection of the
target polling rate from the flags page.

BUG=855188

Change-Id: I9ec58c7320eff952c46bce263da8526459ad8a9b
Reviewed-on: https://chromium-review.googlesource.com/1110742
Commit-Queue: Matt Reynolds <mattreynolds@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Reviewed-by: Brandon Jones <bajones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#571227}