The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/ec065b62900a6db60548604dc7828a3db144b1f9

commit ec065b62900a6db60548604dc7828a3db144b1f9
Author: Raymond Toy <rtoy@chromium.org>
Date: Tue Jun 26 17:49:17 2018

Record whether an AudioContext had a node started

Bug:  855070 
Change-Id: If5adab90c16f3ef4d074c1b31a5d952b9cd0a0c3
Reviewed-on: https://chromium-review.googlesource.com/1112380
Commit-Queue: Raymond Toy <rtoy@chromium.org>
Reviewed-by: Mounir Lamouri <mlamouri@chromium.org>
Reviewed-by: Steven Holte <holte@chromium.org>
Cr-Commit-Position: refs/heads/master@{#570458}
[modify] https://crrev.com/ec065b62900a6db60548604dc7828a3db144b1f9/third_party/blink/renderer/modules/webaudio/audio_context.cc
[modify] https://crrev.com/ec065b62900a6db60548604dc7828a3db144b1f9/third_party/blink/renderer/modules/webaudio/audio_context.h
[modify] https://crrev.com/ec065b62900a6db60548604dc7828a3db144b1f9/tools/metrics/ukm/ukm.xml