Revert of [worklets] Introduce ThreadedWorkletMessagingProxy and AnimationWorkletMessagaingProxy.

third_party/WebKit/Source/modules/compositorworker/AnimationWorkletMessagingProxy.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 AnimationWorkletMessagingProxy_h
-#define AnimationWorkletMessagingProxy_h
-
-#include "core/workers/ThreadedWorkletMessagingProxy.h"
-#include "wtf/Allocator.h"
-#include <memory>
-
-namespace blink {
-
-class ExecutionContext;
-class WorkerThread;
-
-class AnimationWorkletMessagingProxy final : public ThreadedWorkletMessagingProxy {
-    USING_FAST_MALLOC(AnimationWorkletMessagingProxy);
-public:
-    explicit AnimationWorkletMessagingProxy(ExecutionContext*);
-
-protected:
-    ~AnimationWorkletMessagingProxy() override;
-
-    std::unique_ptr<WorkerThread> createWorkerThread(double originTime) override;
-};
-
-} // namespace blink
-
-#endif // AnimationWorkletMessagingProxy_h