The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/383b95ed4509e05eaf33a19b057af37d04b1d937

commit 383b95ed4509e05eaf33a19b057af37d04b1d937
Author: Hongchan Choi <hongchan@chromium.org>
Date: Wed Jul 12 17:30:05 2017

Implement AudioParamMap

AudioParamMap is a map-like container owned by AudioWorkletNode object.
It associates the name of a parameter to the actual AudioParam object.

Spec: https://webaudio.github.io/web-audio-api/#idl-def-AudioParamMap

Bug:  736781 
Change-Id: I063add4281954036b90442dc5c4a6e9c50145e41
Reviewed-on: https://chromium-review.googlesource.com/548239
Commit-Queue: Hongchan Choi <hongchan@chromium.org>
Reviewed-by: Kent Tamura <tkent@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Raymond Toy <rtoy@chromium.org>
Reviewed-by: Takashi Toyoshima <toyoshim@chromium.org>
Cr-Commit-Position: refs/heads/master@{#486007}
[modify] https://crrev.com/383b95ed4509e05eaf33a19b057af37d04b1d937/third_party/WebKit/LayoutTests/virtual/service-worker-navigation-preload-disabled/webexposed/global-interface-listing-expected.txt
[modify] https://crrev.com/383b95ed4509e05eaf33a19b057af37d04b1d937/third_party/WebKit/LayoutTests/webexposed/global-interface-listing-expected.txt
[modify] https://crrev.com/383b95ed4509e05eaf33a19b057af37d04b1d937/third_party/WebKit/Source/modules/modules_idl_files.gni
[add] https://crrev.com/383b95ed4509e05eaf33a19b057af37d04b1d937/third_party/WebKit/Source/modules/webaudio/AudioParamMap.cpp
[add] https://crrev.com/383b95ed4509e05eaf33a19b057af37d04b1d937/third_party/WebKit/Source/modules/webaudio/AudioParamMap.h
[add] https://crrev.com/383b95ed4509e05eaf33a19b057af37d04b1d937/third_party/WebKit/Source/modules/webaudio/AudioParamMap.idl
[modify] https://crrev.com/383b95ed4509e05eaf33a19b057af37d04b1d937/third_party/WebKit/Source/modules/webaudio/BUILD.gn