Hold this change until there is an active PR.

The silence hint will not happen in V1 (if at all).  The optimized AudioParam issue has been updated so it is part of the spec now.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/ccfa5609adc431413c57adf9ace86731a41b011d

commit ccfa5609adc431413c57adf9ace86731a41b011d
Author: Raymond Toy <rtoy@chromium.org>
Date: Tue Jul 10 23:34:32 2018

If AudioWorklet AudioParam is constant, make the array have length 1

If the AudioParam is constant over a rendering quantum, we're allowed
to set the parameter value array to have a length one to indicate that
the audio param is constant.

Make this so if the audio param is truly constant.

Bug:  814796 
Test: audioworklet-audioparam-size.https.html
Change-Id: Ib6e5805dbeb418ad3c202c9c79adc87bc93dad4a
Reviewed-on: https://chromium-review.googlesource.com/1097977
Reviewed-by: Hongchan Choi <hongchan@chromium.org>
Commit-Queue: Raymond Toy <rtoy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#573985}
[add] https://crrev.com/ccfa5609adc431413c57adf9ace86731a41b011d/third_party/WebKit/LayoutTests/external/wpt/webaudio/the-audio-api/the-audioworklet-interface/audioworklet-audioparam-size.https.html
[modify] https://crrev.com/ccfa5609adc431413c57adf9ace86731a41b011d/third_party/WebKit/LayoutTests/external/wpt/webaudio/the-audio-api/the-audioworklet-interface/processors/gain-processor.js
[add] https://crrev.com/ccfa5609adc431413c57adf9ace86731a41b011d/third_party/WebKit/LayoutTests/external/wpt/webaudio/the-audio-api/the-audioworklet-interface/processors/param-size-processor.js
[modify] https://crrev.com/ccfa5609adc431413c57adf9ace86731a41b011d/third_party/blink/renderer/modules/webaudio/audio_worklet_global_scope.cc