The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/2e26abbb6308b28c8b8e45f9438bd3a6c4463add

commit 2e26abbb6308b28c8b8e45f9438bd3a6c4463add
Author: Hongchan Choi <hongchan@chromium.org>
Date: Fri Nov 17 05:01:15 2017

Implements AudioWorkletProcessorState in AudioWorkletNode

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

This CL has 2 development steps:

1. Implements AudioWorkletProcessorState in AudioWorkletNode
  - This change is relatively simple, and will cover two processor state
    changes: "pending", "running".
2. Implements the communication channel from AudioWorkletGlobalScope to
   the main execution context and an AudioWorkletNode instance.
  - This change is slightly more involved. AWGS needs a reference to the
    parent frame task runner, so it can fire the processor state change
    event like "stopped" and "error".

Bug:  784526 
Test: LayoutTests/http/tests/webaudio/audio-worklet/audio-worklet-processor-state.html
Change-Id: If2dcae7c6dd8308d1905e7b8ae9cd4736b871dc6
Reviewed-on: https://chromium-review.googlesource.com/769330
Commit-Queue: Hongchan Choi <hongchan@chromium.org>
Reviewed-by: Raymond Toy <rtoy@chromium.org>
Reviewed-by: Hiroki Nakagawa <nhiroki@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#517307}
[add] https://crrev.com/2e26abbb6308b28c8b8e45f9438bd3a6c4463add/third_party/WebKit/LayoutTests/http/tests/webaudio/audio-worklet/audio-worklet-processor-state.html
[add] https://crrev.com/2e26abbb6308b28c8b8e45f9438bd3a6c4463add/third_party/WebKit/LayoutTests/http/tests/webaudio/audio-worklet/state-processor.js
[modify] https://crrev.com/2e26abbb6308b28c8b8e45f9438bd3a6c4463add/third_party/WebKit/Source/core/events/event_type_names.json5
[modify] https://crrev.com/2e26abbb6308b28c8b8e45f9438bd3a6c4463add/third_party/WebKit/Source/modules/webaudio/AudioWorkletGlobalScope.cpp
[modify] https://crrev.com/2e26abbb6308b28c8b8e45f9438bd3a6c4463add/third_party/WebKit/Source/modules/webaudio/AudioWorkletNode.cpp
[modify] https://crrev.com/2e26abbb6308b28c8b8e45f9438bd3a6c4463add/third_party/WebKit/Source/modules/webaudio/AudioWorkletNode.h
[modify] https://crrev.com/2e26abbb6308b28c8b8e45f9438bd3a6c4463add/third_party/WebKit/Source/modules/webaudio/AudioWorkletNode.idl
[modify] https://crrev.com/2e26abbb6308b28c8b8e45f9438bd3a6c4463add/third_party/WebKit/Source/modules/webaudio/AudioWorkletProcessor.cpp
[modify] https://crrev.com/2e26abbb6308b28c8b8e45f9438bd3a6c4463add/third_party/WebKit/Source/modules/webaudio/AudioWorkletProcessor.h

 Issue 774565  has been merged into this issue.