CL is available at https://chromium-review.googlesource.com/c/chromium/src/+/874615, but apparently fling scrolling will break temporarily with the fallback UI CL being landed in the near future, so we're waiting on that to be fixed before landing the test.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/b40132aa0581f97f6751b30c47fd0740100bdc82

commit b40132aa0581f97f6751b30c47fd0740100bdc82
Author: bsheedy <bsheedy@chromium.org>
Date: Fri Mar 09 00:08:44 2018

Add VR Browser fling scroll test

Adds a test to ensure that quickly scrolling on the Daydream
controller's touchpad in the VR Browser results in a fling scroll.

Also refactors some related test code to reduce duplication between test
cases.

Bug:  762213 
Change-Id: I6a041a6051c9bfc0648c90b04a8a44b06261ae9d
Reviewed-on: https://chromium-review.googlesource.com/874615
Commit-Queue: Brian Sheedy <bsheedy@chromium.org>
Reviewed-by: Michael Thiessen <mthiesse@chromium.org>
Cr-Commit-Position: refs/heads/master@{#541947}
[modify] https://crrev.com/b40132aa0581f97f6751b30c47fd0740100bdc82/chrome/android/javatests/src/org/chromium/chrome/browser/vr_shell/EmulatedVrController.java
[modify] https://crrev.com/b40132aa0581f97f6751b30c47fd0740100bdc82/chrome/android/javatests/src/org/chromium/chrome/browser/vr_shell/VrShellControllerInputTest.java

This has been automated now.