Destruct base::Thread before WorkerThread::terminateAndWait returns

third_party/WebKit/Source/modules/compositorworker/AbstractAnimationWorkletThread.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 AbstractAnimationWorkletThread_h
 #define AbstractAnimationWorkletThread_h
 
 #include "core/workers/WorkerLoaderProxy.h"
 #include "core/workers/WorkerThread.h"
 #include "modules/ModulesExport.h"
 #include <memory>
 
 namespace blink {
 
 class WorkerReportingProxy;
 
 // TODO(ikilpatrick): Remove this class up to AnimationWorkletThread once we no
 // longer have CompositorWorker.
 class MODULES_EXPORT AbstractAnimationWorkletThread : public WorkerThread {
 public:
     ~AbstractAnimationWorkletThread() override;
 
     WorkerBackingThread& workerBackingThread() override;
+    void clearWorkerBackingThread() override
+    {
+        // Do nothing.
+        // The backing thread is cleared by clearSharedBackingThread().
+    }
+
     bool shouldAttachThreadDebugger() const override { return false; }
 
     static void ensureSharedBackingThread();
     static void createSharedBackingThreadForTest();
 
     static void clearSharedBackingThread();
 
 protected:
     AbstractAnimationWorkletThread(PassRefPtr<WorkerLoaderProxy>, WorkerReportingProxy&);
 
     bool isOwningBackingThread() const override { return false; }
 };
 
 } // namespace blink
 
 #endif // AbstractAnimationWorkletThread_h