[WIP] Worklet: Merge MainThreadWorklet and ThreadedWorklet into Worklet

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/V8BindingForCore.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)
-    : ThreadedWorklet(frame), worklet_messaging_proxy_(nullptr) {}
+AudioWorklet::AudioWorklet(LocalFrame* frame) : Worklet(frame) {}
 
 AudioWorklet::~AudioWorklet() {
-  if (worklet_messaging_proxy_)
-    worklet_messaging_proxy_->ParentObjectDestroyed();
+  // The proxy outlives the worklet as it is used to perform thread shutdown,
+  // it deletes itself once this has occurred.
+  // TODO(nhiroki):
 }
 
-void AudioWorklet::Initialize() {
-  AudioWorkletThread::EnsureSharedBackingThread();
-
-  DCHECK(!worklet_messaging_proxy_);
-  DCHECK(GetExecutionContext());
-
-  worklet_messaging_proxy_ =
-      new AudioWorkletMessagingProxy(GetExecutionContext());
-  worklet_messaging_proxy_->Initialize();
+bool AudioWorklet::NeedsToCreateGlobalScope() {
+  // In the current impl, we create only one global scope.
+  return !GetNumberOfGlobalScopes();
 }
 
-bool AudioWorklet::IsInitialized() const {
-  return worklet_messaging_proxy_;
-}
-
-WorkletGlobalScopeProxy* AudioWorklet::GetWorkletGlobalScopeProxy() const {
-  DCHECK(worklet_messaging_proxy_);
-  return worklet_messaging_proxy_;
+std::unique_ptr<WorkletGlobalScopeProxy> AudioWorklet::CreateGlobalScope() {
+  AudioWorkletThread::EnsureSharedBackingThread();
+  return WTF::MakeUnique<AudioWorkletMessagingProxy>(GetExecutionContext());
 }
 
 DEFINE_TRACE(AudioWorklet) {
-  ThreadedWorklet::Trace(visitor);
+  Worklet::Trace(visitor);
 }
 
 }  // namespace blink