[WIP] Worklet: Merge MainThreadWorklet and ThreadedWorklet into Worklet

third_party/WebKit/Source/modules/csspaint/PaintWorklet.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/csspaint/PaintWorklet.h"
 
 #include "bindings/core/v8/V8BindingForCore.h"
 #include "core/dom/Document.h"
 #include "core/frame/LocalFrame.h"
 #include "modules/csspaint/PaintWorkletGlobalScope.h"
 
 namespace blink {
 
 // static
 PaintWorklet* PaintWorklet::Create(LocalFrame* frame) {
   return new PaintWorklet(frame);
 }
 
 PaintWorklet::PaintWorklet(LocalFrame* frame)
-    : MainThreadWorklet(frame),
+    : Worklet(frame),
       pending_generator_registry_(new PaintWorkletPendingGeneratorRegistry) {}
 
 PaintWorklet::~PaintWorklet() = default;
 
 CSSPaintDefinition* PaintWorklet::FindDefinition(const String& name) {
   if (GetNumberOfGlobalScopes() == 0)
     return nullptr;
 
   PaintWorkletGlobalScopeProxy* proxy =
       PaintWorkletGlobalScopeProxy::From(FindAvailableGlobalScope());
   return proxy->FindDefinition(name);
 }
 
 void PaintWorklet::AddPendingGenerator(const String& name,
                                        CSSPaintImageGeneratorImpl* generator) {
   pending_generator_registry_->AddPendingGenerator(name, generator);
 }
 
 DEFINE_TRACE(PaintWorklet) {
   visitor->Trace(pending_generator_registry_);
-  MainThreadWorklet::Trace(visitor);
+  Worklet::Trace(visitor);
 }
 
 bool PaintWorklet::NeedsToCreateGlobalScope() {
   // "The user agent must have, and select from at least two
   // PaintWorkletGlobalScopes in the worklet's WorkletGlobalScopes list, unless
   // the user agent is under memory constraints."
   // https://drafts.css-houdini.org/css-paint-api-1/#drawing-an-image
   // TODO(nhiroki): In the current impl, we create only one global scope. We
   // should create at least two global scopes as the spec.
   return !GetNumberOfGlobalScopes();
 }
 
 std::unique_ptr<WorkletGlobalScopeProxy> PaintWorklet::CreateGlobalScope() {
   return WTF::MakeUnique<PaintWorkletGlobalScopeProxy>(
       ToDocument(GetExecutionContext())->GetFrame(),
       pending_generator_registry_);
 }
 
 }  // namespace blink