Introduce WorkletGlobalScopeProxy interface.

third_party/WebKit/Source/modules/compositorworker/CompositorWorklet.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 CompositorWorklet_h
+#define CompositorWorklet_h
+
+#include "modules/ModulesExport.h"
+#include "modules/worklet/Worklet.h"
+#include "platform/heap/Handle.h"
+
+namespace blink {
+
+class CompositorWorkletGlobalScopeProxy;
+
+class MODULES_EXPORT CompositorWorklet final : public Worklet {
+    WTF_MAKE_NONCOPYABLE(CompositorWorklet);
+public:
+    static CompositorWorklet* create(LocalFrame*, ExecutionContext*);
+    ~CompositorWorklet() override;
+
+    WorkletGlobalScopeProxy* workletGlobalScopeProxy() const final;
+
+    DECLARE_VIRTUAL_TRACE();
+
+private:
+    CompositorWorklet(LocalFrame*, ExecutionContext*);
+
+    CompositorWorkletGlobalScopeProxy* m_workletGlobalScopeProxy;
+};
+
+} // namespace blink
+
+#endif // CompositorWorklet_h