CompositorWorkerProxyClientImpl to CompositorProxy cross thread reference is using WeakMember

third_party/WebKit/Source/core/dom/CompositorWorkerProxyClient.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 CompositorWorkerProxyClient_h
 #define CompositorWorkerProxyClient_h
 
 #include "core/CoreExport.h"
 #include "core/dom/CompositorProxyClient.h"
 #include "core/workers/WorkerClients.h"
 #include "wtf/Noncopyable.h"
 
 namespace blink {
 
 class WorkerClients;
 class WorkerGlobalScope;
 
 class CORE_EXPORT CompositorWorkerProxyClient
-    : public CompositorProxyClient,
-      public Supplement<WorkerClients> {
+    : public Supplement<WorkerClients> {
   WTF_MAKE_NONCOPYABLE(CompositorWorkerProxyClient);
-  USING_GARBAGE_COLLECTED_MIXIN(CompositorWorkerProxyClient);
 
  public:
   CompositorWorkerProxyClient() {}
-  DEFINE_INLINE_VIRTUAL_TRACE() {
-    CompositorProxyClient::trace(visitor);
-    Supplement<WorkerClients>::trace(visitor);
-  }
 
   static CompositorWorkerProxyClient* from(WorkerClients*);
   static const char* supplementName();
 
   virtual void dispose() = 0;
   virtual void setGlobalScope(WorkerGlobalScope*) = 0;
   virtual void requestAnimationFrame() = 0;
+  virtual CompositorProxyClient* compositorProxyClient() = 0;
 };
 
 CORE_EXPORT void provideCompositorWorkerProxyClientTo(
     WorkerClients*,
     CompositorWorkerProxyClient*);
 
 }  // namespace blink
 
 #endif  // CompositorWorkerProxyClient_h