The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/a26c0c1c9e16402ae974dfa97e580687c2c7b23e

commit a26c0c1c9e16402ae974dfa97e580687c2c7b23e
Author: Michael Thiessen <mthiesse@chromium.org>
Date: Tue Aug 29 22:18:13 2017

VR: Ensure input is handled even when WebVR is not submitting frames.

The moves controller event handling into OnVSync for WebVR rendering so
that even if WebVR misses frames or misbehaves, we immediately handle
app button presses.

Bug:  759772 
Change-Id: I364339289fec89412f5d6e03756673e7606d1fbe
Reviewed-on: https://chromium-review.googlesource.com/639371
Commit-Queue: Michael Thiessen <mthiesse@chromium.org>
Reviewed-by: Christopher Grant <cjgrant@chromium.org>
Cr-Commit-Position: refs/heads/master@{#498253}
[modify] https://crrev.com/a26c0c1c9e16402ae974dfa97e580687c2c7b23e/chrome/android/javatests/src/org/chromium/chrome/browser/vr_shell/WebVrInputTest.java
[modify] https://crrev.com/a26c0c1c9e16402ae974dfa97e580687c2c7b23e/chrome/browser/android/vr_shell/vr_shell_gl.cc
[modify] https://crrev.com/a26c0c1c9e16402ae974dfa97e580687c2c7b23e/chrome/browser/android/vr_shell/vr_shell_gl.h
[add] https://crrev.com/a26c0c1c9e16402ae974dfa97e580687c2c7b23e/chrome/test/data/android/webvr_instrumentation/html/webvr_page_submits_once.html
[modify] https://crrev.com/a26c0c1c9e16402ae974dfa97e580687c2c7b23e/chrome/test/data/android/webvr_instrumentation/resources/webvr_boilerplate.js

Michael, is there a way I can manually verify this? Is there a WebVR page that doesn't submit any frames?

There currently isn't, I was testing with a page hosted on localhost :/

Maybe we should create a test site with malicious/poorly behaving webVR pages.