CompositorWorkerProxyClientImpl to CompositorProxy cross thread reference is using WeakMember

third_party/WebKit/Source/web/CompositorWorkerProxyClientImpl.h

 // Copyright 2015 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 CompositorWorkerProxyClientImpl_h
 #define CompositorWorkerProxyClientImpl_h
 
 #include "core/dom/CompositorWorkerProxyClient.h"
 #include "platform/heap/Handle.h"
 #include "web/CompositorAnimator.h"
+#include "web/CompositorProxyClientImpl.h"
 #include "wtf/Noncopyable.h"
 
 namespace blink {
 
 class CompositorMutableStateProvider;
 class CompositorMutatorImpl;
 class CompositorWorkerGlobalScope;
 class WorkerGlobalScope;
 
 // Mediates between one CompositorWorkerGlobalScope and the associated
 // CompositorMutatorImpl. There is one CompositorWorkerProxyClientImpl per
 // worker but there may be multiple for a given mutator, e.g. if a single
 // document creates multiple CompositorWorker objects.
 //
+// Owned by the main thread.
 // Should be accessed only on the compositor thread.
 class CompositorWorkerProxyClientImpl final
-    : public CompositorWorkerProxyClient,
+    : public GarbageCollectedFinalized<CompositorWorkerProxyClientImpl>,
+      public CompositorWorkerProxyClient,
       public CompositorAnimator {
   WTF_MAKE_NONCOPYABLE(CompositorWorkerProxyClientImpl);
   USING_GARBAGE_COLLECTED_MIXIN(CompositorWorkerProxyClientImpl);
 
  public:
   explicit CompositorWorkerProxyClientImpl(CompositorMutatorImpl*);
   DECLARE_TRACE();
 
   // CompositorAnimator:
   bool mutate(double monotonicTimeNow,
               CompositorMutableStateProvider*) override;
 
   // CompositorWorkerProxyClient:
   void dispose() override;
   void setGlobalScope(WorkerGlobalScope*) override;
   void requestAnimationFrame() override;
-  void registerCompositorProxy(CompositorProxy*) override;
-  void unregisterCompositorProxy(CompositorProxy*) override;
+  CompositorProxyClient* compositorProxyClient() override {
+    return m_compositorProxyClient.get();
+  };
 
  private:
   bool executeAnimationFrameCallbacks(double monotonicTimeNow);
 
   CrossThreadPersistent<CompositorMutatorImpl> m_mutator;
 
   CrossThreadPersistent<CompositorWorkerGlobalScope> m_globalScope;
   bool m_requestedAnimationFrameCallbacks;
 
-  // TODO(majidvp): move this out to a separate class that can be composed in.
-  HeapHashSet<WeakMember<CompositorProxy>> m_proxies;
+  CrossThreadPersistent<CompositorProxyClientImpl> m_compositorProxyClient;
 };
 
 }  // namespace blink
 
 #endif  // CompositorWorkerProxyClientImpl_h