[worklets] Split apart CompositorWorkerThread for sharing with AnimationWorkletThread.

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

Index: third_party/WebKit/Source/modules/compositorworker/CompositorWorkerThread.h
diff --git a/third_party/WebKit/Source/modules/compositorworker/CompositorWorkerThread.h b/third_party/WebKit/Source/modules/compositorworker/CompositorWorkerThread.h
index e8f7de7289b610d42df9ea52b16135f96c3f6ec1..beb411e0247d3bafeef4d0d1f5224e841102ba5e 100644
--- a/third_party/WebKit/Source/modules/compositorworker/CompositorWorkerThread.h
+++ b/third_party/WebKit/Source/modules/compositorworker/CompositorWorkerThread.h
@@ -5,36 +5,28 @@
 #ifndef CompositorWorkerThread_h
 #define CompositorWorkerThread_h
 
-#include "core/workers/WorkerThread.h"
 #include "modules/ModulesExport.h"
+#include "modules/compositorworker/AbstractCompositorWorkerThread.h"
 #include <memory>
 
 namespace blink {
 
 class InProcessWorkerObjectProxy;
 
-class MODULES_EXPORT CompositorWorkerThread final : public WorkerThread {
+class MODULES_EXPORT CompositorWorkerThread final : public AbstractCompositorWorkerThread {
 public:
     static std::unique_ptr<CompositorWorkerThread> create(PassRefPtr<WorkerLoaderProxy>, InProcessWorkerObjectProxy&, double timeOrigin);
     ~CompositorWorkerThread() override;
 
     InProcessWorkerObjectProxy& workerObjectProxy() const { return m_workerObjectProxy; }
-    WorkerBackingThread& workerBackingThread() override;
     ConsoleMessageStorage* consoleMessageStorage() final;
-    bool shouldAttachThreadDebugger() const override { return false; }
-
-    static void ensureSharedBackingThread();
-    static void createSharedBackingThreadForTest();
-
-    static void clearSharedBackingThread();
 
 protected:
-    CompositorWorkerThread(PassRefPtr<WorkerLoaderProxy>, InProcessWorkerObjectProxy&, double timeOrigin);
-
     WorkerOrWorkletGlobalScope* createWorkerGlobalScope(std::unique_ptr<WorkerThreadStartupData>) override;
-    bool isOwningBackingThread() const override { return false; }
 
 private:
+    CompositorWorkerThread(PassRefPtr<WorkerLoaderProxy>, InProcessWorkerObjectProxy&, double timeOrigin);
+
     InProcessWorkerObjectProxy& m_workerObjectProxy;
     double m_timeOrigin;
 };