[worklets] Split apart CompositorWorkerThread for sharing with AnimationWorkletThread.

third_party/WebKit/Source/modules/compositorworker/AnimationWorkletThread.h

+// 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.
+
+#ifndef AnimationWorkletThread_h
+#define AnimationWorkletThread_h
+
+#include "modules/ModulesExport.h"
+#include "modules/compositorworker/AbstractAnimationWorkletThread.h"
+#include <memory>
+
+namespace blink {
+
+class WorkerReportingProxy;
+
+class MODULES_EXPORT AnimationWorkletThread final : public AbstractAnimationWorkletThread {
+public:
+    static std::unique_ptr<AnimationWorkletThread> create(PassRefPtr<WorkerLoaderProxy>, WorkerReportingProxy&);
+    ~AnimationWorkletThread() override;
+
+protected:
+    WorkerOrWorkletGlobalScope* createWorkerGlobalScope(std::unique_ptr<WorkerThreadStartupData>) final;
+
+private:
+    AnimationWorkletThread(PassRefPtr<WorkerLoaderProxy>, WorkerReportingProxy&);
+};
+
+} // namespace blink
+
+#endif // AnimationWorkletThread_h