CompositorWorkerProxyClientImpl to CompositorProxy cross thread reference is using WeakMember

third_party/WebKit/Source/web/CompositorWorkerProxyClientImpl.cpp

 // 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.
 
 #include "web/CompositorWorkerProxyClientImpl.h"
 
 #include "core/dom/CompositorProxy.h"
 #include "modules/compositorworker/CompositorWorkerGlobalScope.h"
 #include "platform/graphics/CompositorMutableStateProvider.h"
 #include "platform/instrumentation/tracing/TraceEvent.h"
 #include "web/CompositorMutatorImpl.h"
 #include "wtf/CurrentTime.h"
 
 namespace blink {
 
 // A helper class that updates proxies mutable state on creation and reset it
 // on destruction. This can be used with rAF callback to ensure no mutation is
 // allowed outside rAF.
 class ScopedCompositorMutableState final {
   WTF_MAKE_NONCOPYABLE(ScopedCompositorMutableState);
   STACK_ALLOCATED();
 
  public:
-  ScopedCompositorMutableState(
-      HeapHashSet<WeakMember<CompositorProxy>>& proxies,
-      CompositorMutableStateProvider* stateProvider)
-      : m_proxies(proxies) {
-    for (CompositorProxy* proxy : m_proxies) {
+  ScopedCompositorMutableState(CompositorProxyClientImpl* compositorProxyClient,
+                               CompositorMutableStateProvider* stateProvider)
+      : m_compositorProxyClient(compositorProxyClient) {
+    DCHECK(!isMainThread());
+    DCHECK(m_compositorProxyClient);
+    for (CompositorProxy* proxy : m_compositorProxyClient->proxies()) {
       proxy->takeCompositorMutableState(
           stateProvider->getMutableStateFor(proxy->elementId()));
     }
   }
   ~ScopedCompositorMutableState() {
-    for (CompositorProxy* proxy : m_proxies)
+    for (CompositorProxy* proxy : m_compositorProxyClient->proxies())
       proxy->takeCompositorMutableState(nullptr);
   }
 
  private:
-  HeapHashSet<WeakMember<CompositorProxy>>& m_proxies;
+  Member<CompositorProxyClientImpl> m_compositorProxyClient;
 };
 
 CompositorWorkerProxyClientImpl::CompositorWorkerProxyClientImpl(
     CompositorMutatorImpl* mutator)
-    : m_mutator(mutator), m_globalScope(nullptr) {
+    : m_mutator(mutator) {
   DCHECK(isMainThread());
 }
 
 DEFINE_TRACE(CompositorWorkerProxyClientImpl) {
-  visitor->trace(m_proxies);
   CompositorAnimator::trace(visitor);
   CompositorWorkerProxyClient::trace(visitor);
 }
 
 void CompositorWorkerProxyClientImpl::setGlobalScope(WorkerGlobalScope* scope) {
+  DCHECK(!isMainThread());
   TRACE_EVENT0("compositor-worker",
                "CompositorWorkerProxyClientImpl::setGlobalScope");
   DCHECK(!m_globalScope);
+  DCHECK(!m_compositorProxyClient);
   DCHECK(scope);
   m_globalScope = static_cast<CompositorWorkerGlobalScope*>(scope);
   m_mutator->registerCompositorAnimator(this);
+  m_compositorProxyClient = new CompositorProxyClientImpl();
 }
 
 void CompositorWorkerProxyClientImpl::dispose() {
+  DCHECK(!isMainThread());
   // CompositorWorkerProxyClientImpl and CompositorMutatorImpl form a reference
   // cycle. CompositorWorkerGlobalScope and CompositorWorkerProxyClientImpl
   // also form another big reference cycle. So dispose needs to be called on
   // Worker termination to break these cycles. If not, layout test leak
   // detection will report a WorkerGlobalScope leak.
   m_mutator->unregisterCompositorAnimator(this);
   m_globalScope = nullptr;
 }
 
 void CompositorWorkerProxyClientImpl::requestAnimationFrame() {
+  DCHECK(!isMainThread());
   TRACE_EVENT0("compositor-worker",
                "CompositorWorkerProxyClientImpl::requestAnimationFrame");
   m_requestedAnimationFrameCallbacks = true;
   m_mutator->setNeedsMutate();
 }
 
 bool CompositorWorkerProxyClientImpl::mutate(
     double monotonicTimeNow,
     CompositorMutableStateProvider* stateProvider) {
+  DCHECK(!isMainThread());
   if (!m_globalScope)
     return false;
 
   TRACE_EVENT0("compositor-worker", "CompositorWorkerProxyClientImpl::mutate");
   if (!m_requestedAnimationFrameCallbacks)
     return false;
 
   {
-    ScopedCompositorMutableState mutableState(m_proxies, stateProvider);
+    ScopedCompositorMutableState mutableState(m_compositorProxyClient,
+                                              stateProvider);
     m_requestedAnimationFrameCallbacks =
         executeAnimationFrameCallbacks(monotonicTimeNow);
   }
 
   return m_requestedAnimationFrameCallbacks;
 }
 
 bool CompositorWorkerProxyClientImpl::executeAnimationFrameCallbacks(
     double monotonicTimeNow) {
+  DCHECK(!isMainThread());
   TRACE_EVENT0(
       "compositor-worker",
       "CompositorWorkerProxyClientImpl::executeAnimationFrameCallbacks");
 
   DCHECK(m_globalScope);
   // Convert to zero based document time in milliseconds consistent with
   // requestAnimationFrame.
   double highResTimeMs =
       1000.0 * (monotonicTimeNow - m_globalScope->timeOrigin());
   return m_globalScope->executeAnimationFrameCallbacks(highResTimeMs);
 }
 
-void CompositorWorkerProxyClientImpl::registerCompositorProxy(
-    CompositorProxy* proxy) {
-  m_proxies.insert(proxy);
-}
-
-void CompositorWorkerProxyClientImpl::unregisterCompositorProxy(
-    CompositorProxy* proxy) {
-  m_proxies.erase(proxy);
-}
-
 }  // namespace blink