Worklet: Separate Worklet into MainThreadWorklet and ThreadedWorklet

third_party/WebKit/Source/modules/webaudio/AudioWorklet.cpp

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "modules/webaudio/AudioWorklet.h"
 
 #include "bindings/core/v8/V8Binding.h"
 #include "core/dom/Document.h"
 #include "core/frame/LocalFrame.h"
 #include "modules/webaudio/AudioWorkletMessagingProxy.h"
 #include "modules/webaudio/AudioWorkletThread.h"
 
 namespace blink {
 
 AudioWorklet* AudioWorklet::Create(LocalFrame* frame) {
   return new AudioWorklet(frame);
 }
 
 AudioWorklet::AudioWorklet(LocalFrame* frame)
-    : Worklet(frame), worklet_messaging_proxy_(nullptr) {}
+    : ThreadedWorklet(frame), worklet_messaging_proxy_(nullptr) {}
 
 AudioWorklet::~AudioWorklet() {
   if (worklet_messaging_proxy_)
     worklet_messaging_proxy_->ParentObjectDestroyed();
 }
 
 void AudioWorklet::Initialize() {
   AudioWorkletThread::EnsureSharedBackingThread();
 
   DCHECK(!worklet_messaging_proxy_);
   DCHECK(GetExecutionContext());
 
   worklet_messaging_proxy_ =
       new AudioWorkletMessagingProxy(GetExecutionContext());
   worklet_messaging_proxy_->Initialize();
 }
 
 bool AudioWorklet::IsInitialized() const {
   return worklet_messaging_proxy_;
 }
 
 WorkletGlobalScopeProxy* AudioWorklet::GetWorkletGlobalScopeProxy() const {
   DCHECK(worklet_messaging_proxy_);
   return worklet_messaging_proxy_;
 }
 
 DEFINE_TRACE(AudioWorklet) {
-  Worklet::Trace(visitor);
+  ThreadedWorklet::Trace(visitor);
 }
 
 }  // namespace blink