Oilpan: Remove raw pointer to ExecutionContext from WorkerInspectorProxy

Source/core/workers/WorkerInspectorProxy.h

 // Copyright 2014 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 WorkerInspectorProxy_h
 #define WorkerInspectorProxy_h
 
 #include "core/CoreExport.h"
+#include "platform/heap/Handle.h"
 #include "public/platform/WebThread.h"
 #include "wtf/Forward.h"
 
 namespace blink {
 
 class ExecutionContext;
 class KURL;
 class WebTraceLocation;
 class WorkerGlobalScopeProxy;
 class WorkerThread;
 
 // A proxy for talking to the worker inspector on the worker thread.
 // All of these methods should be called on the main thread.
-class CORE_EXPORT WorkerInspectorProxy final {
+class CORE_EXPORT WorkerInspectorProxy final : public NoBaseWillBeGarbageCollectedFinalized<WorkerInspectorProxy> {
 public:
-    static PassOwnPtr<WorkerInspectorProxy> create();
+    static PassOwnPtrWillBeRawPtr<WorkerInspectorProxy> create();
 
     ~WorkerInspectorProxy();
+    DECLARE_TRACE();
 
-    class PageInspector {
+    class PageInspector : public NoBaseWillBeGarbageCollectedFinalized<PageInspector> {
     public:
         virtual ~PageInspector() { }
         virtual void dispatchMessageFromWorker(const String&) = 0;
         virtual void workerConsoleAgentEnabled(WorkerGlobalScopeProxy*) = 0;
+        DEFINE_INLINE_VIRTUAL_TRACE() { }
     };
 
     void workerThreadCreated(ExecutionContext*, WorkerThread*, const KURL&);
     void workerThreadTerminated();
 
     void connectToInspector(PageInspector*);
     void disconnectFromInspector();
     void sendMessageToInspector(const String&);
     void writeTimelineStartedEvent(const String& sessionId, const String& workerId);
 
     PageInspector* pageInspector() const { return m_pageInspector; }
 
     void setWorkerGlobalScopeProxy(WorkerGlobalScopeProxy* proxy) { m_workerGlobalScopeProxy = proxy; }
     WorkerGlobalScopeProxy* workerGlobalScopeProxy() const { return m_workerGlobalScopeProxy; }
 
 private:
     WorkerInspectorProxy();
 
     void addDebuggerTaskForWorker(const WebTraceLocation&, PassOwnPtr<WebThread::Task>);
 
     WorkerThread* m_workerThread;

[haraken, 2015/07/30 07:47:32]

This raw pointer would be safe since the m_workerThread is explicitly cleared in
workerThreadTerminated().

-    ExecutionContext* m_executionContext;
-    WorkerInspectorProxy::PageInspector* m_pageInspector;
+    RawPtrWillBeMember<ExecutionContext> m_executionContext;
+    RawPtrWillBeMember<WorkerInspectorProxy::PageInspector> m_pageInspector;
     WorkerGlobalScopeProxy* m_workerGlobalScopeProxy;

[haraken, 2015/07/30 07:47:32]

I guess this pointer has a risk of becoming a stale pointer if:

1) WorkerGlobalScopeProxy gets destroyed.
2) GC is triggered and the WorkerInspectorProxy gets collected.

Between 1) and 2), WorkerInspectorProxy::m_workerGlobalScopeProxy can be stale.
I think you need to call:

   m_workerInspectorProxy->setWorkerGlobalScopeProxy(nullptr);

in WorkerMessagingProxy's destructor.

[keishi, 2015/08/03 09:35:56]

Done.

 };
 
 } // namespace blink
 
 #endif // WorkerInspectorProxy_h