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);
@@ skipping 36 matching lines @@
 {
     m_proxies.add(proxy);
 }
 
 void CompositorProxyClientImpl::unregisterCompositorProxy(CompositorProxy* proxy)
 {
     m_proxies.remove(proxy);
 }
 
 } // namespace blink