Prepare CompositorWorker for per thread heap

third_party/WebKit/Source/web/CompositorProxyClientImpl.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/CompositorProxyClientImpl.h"
 
 #include "core/dom/CompositorProxy.h"
 #include "modules/compositorworker/CompositorWorkerGlobalScope.h"
 #include "platform/TraceEvent.h"
 #include "platform/graphics/CompositorMutableStateProvider.h"
@@ skipping 22 matching lines @@
             proxy->takeCompositorMutableState(nullptr);
     }
 private:
     HeapHashSet<WeakMember<CompositorProxy>>& m_proxies;
 };
 
 CompositorProxyClientImpl::CompositorProxyClientImpl(CompositorMutatorImpl* mutator)
     : m_mutator(mutator)
     , m_globalScope(nullptr)
 {
+    DCHECK(isMainThread());
 }
 
 DEFINE_TRACE(CompositorProxyClientImpl)
 {
     CompositorProxyClient::trace(visitor);
-    visitor->trace(m_mutator);
-    visitor->trace(m_globalScope);
     visitor->trace(m_proxies);
 }
 
 void CompositorProxyClientImpl::setGlobalScope(WorkerGlobalScope* scope)
 {
     TRACE_EVENT0("compositor-worker", "CompositorProxyClientImpl::setGlobalScope");
     DCHECK(!m_globalScope);
     DCHECK(scope);
     m_globalScope = static_cast<CompositorWorkerGlobalScope*>(scope);
     m_mutator->registerProxyClient(this);
 }
 
+void CompositorProxyClientImpl::dispose()
+{
+    // CompositorProxyClientImpl and CompositorMutatorImpl form a reference
+    // cycle. CompositorWorkerGlobalScope and CompositorProxyClientImpl
+    // 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->unregisterProxyClient(this);
+    m_globalScope = nullptr;
+}
+
 void CompositorProxyClientImpl::requestAnimationFrame()
 {
     TRACE_EVENT0("compositor-worker", "CompositorProxyClientImpl::requestAnimationFrame");
     m_requestedAnimationFrameCallbacks = true;
     m_mutator->setNeedsMutate();
 }
 
 bool CompositorProxyClientImpl::mutate(double monotonicTimeNow, CompositorMutableStateProvider* stateProvider)
 {
     if (!m_globalScope)
         return false;
 
     TRACE_EVENT0("compositor-worker", "CompositorProxyClientImpl::mutate");
     if (!m_requestedAnimationFrameCallbacks)
         return false;
 
     {
         ScopedCompositorMutableState mutableState(m_proxies, stateProvider);
         m_requestedAnimationFrameCallbacks = executeAnimationFrameCallbacks(monotonicTimeNow);
     }
 
     return m_requestedAnimationFrameCallbacks;
 }
 
 bool CompositorProxyClientImpl::executeAnimationFrameCallbacks(double monotonicTimeNow)
 {
     TRACE_EVENT0("compositor-worker", "CompositorProxyClientImpl::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 CompositorProxyClientImpl::registerCompositorProxy(CompositorProxy* proxy)
 {
     m_proxies.add(proxy);
 }
 
 void CompositorProxyClientImpl::unregisterCompositorProxy(CompositorProxy* proxy)
 {
     m_proxies.remove(proxy);
 }
 
 } // namespace blink