CompositorWorkerProxyClientImpl to CompositorProxy cross thread reference is using WeakMember

third_party/WebKit/Source/web/CompositorMutatorImpl.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 CompositorMutatorImpl_h
 #define CompositorMutatorImpl_h
 
 #include "core/animation/CustomCompositorAnimationManager.h"
 #include "platform/graphics/CompositorMutator.h"
 #include "platform/heap/Handle.h"
 #include "platform/heap/HeapAllocator.h"
 #include "wtf/Noncopyable.h"
 #include <memory>
 
 namespace blink {
 
 class CompositorAnimator;
 class CompositorMutatorClient;
 
 // Fans out requests from the compositor to all of the registered
 // CompositorAnimators which can then mutate layers through their respective
 // mutate interface. Requests for animation frames are received from
 // CompositorAnimators and sent to the compositor to generate a new compositor
 // frame.
 //
+// Owned by the control thread (unless threaded compositing is disabled).
 // Should be accessed only on the compositor thread.
 class CompositorMutatorImpl final : public CompositorMutator {
   WTF_MAKE_NONCOPYABLE(CompositorMutatorImpl);
 
  public:
   static std::unique_ptr<CompositorMutatorClient> createClient();
   static CompositorMutatorImpl* create();
 
   // CompositorMutator implementation.
   bool mutate(double monotonicTimeNow,
@@ skipping 16 matching lines @@
       HashSet<CrossThreadPersistent<CompositorAnimator>>;
   CompositorAnimators m_animators;
 
   std::unique_ptr<CustomCompositorAnimationManager> m_animationManager;
   CompositorMutatorClient* m_client;
 };
 
 }  // namespace blink
 
 #endif  // CompositorMutatorImpl_h