The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/21f460686bb19e1f61eb8d38739aa5a9a9d64559

commit 21f460686bb19e1f61eb8d38739aa5a9a9d64559
Author: Raymond Toy <rtoy@chromium.org>
Date: Mon Oct 16 22:42:04 2017

Remove BiquadFilter.Q histograms

The definition of the Q parameter for lowpass and highpass filters
were changed a while ago in the WebAudio specification.  These
were added to determine how much impact this change would have because
the change is aubible.

It's been over a year, and no bugs have been filed on this, and the
histograms show that the default values are, by far, the most common
values.  Hence, we can remove these histograms.

Bug:  774526 
Test: none
Change-Id: I17ad180a40964bd4d81988492d43e522a47f2f2f
Reviewed-on: https://chromium-review.googlesource.com/718839
Commit-Queue: Raymond Toy <rtoy@chromium.org>
Reviewed-by: Mark Pearson <mpearson@chromium.org>
Reviewed-by: Hongchan Choi <hongchan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#509187}
[modify] https://crrev.com/21f460686bb19e1f61eb8d38739aa5a9a9d64559/third_party/WebKit/Source/modules/webaudio/AudioParam.cpp
[modify] https://crrev.com/21f460686bb19e1f61eb8d38739aa5a9a9d64559/third_party/WebKit/Source/modules/webaudio/AudioParam.h
[modify] https://crrev.com/21f460686bb19e1f61eb8d38739aa5a9a9d64559/third_party/WebKit/Source/modules/webaudio/BiquadFilterNode.cpp
[modify] https://crrev.com/21f460686bb19e1f61eb8d38739aa5a9a9d64559/tools/metrics/histograms/histograms.xml