Oilpan: Move LifecycleNotifier's hierarchy to Oilpan's heap

Source/platform/LifecycleNotifier.h

Index: Source/platform/LifecycleNotifier.h
diff --git a/Source/platform/LifecycleNotifier.h b/Source/platform/LifecycleNotifier.h
index 1f97d775f7f0f9b13941e2baf6528344808d1ab8..8fb6c51df6c953e51c28858c45b1d18a231766de 100644
--- a/Source/platform/LifecycleNotifier.h
+++ b/Source/platform/LifecycleNotifier.h
@@ -34,8 +34,10 @@
 
 namespace blink {
 
+// Using a virtual inheritance to resolve a diamond inheritance
+// in ExecutionContext.
 template<typename T>
-class LifecycleNotifier {
+class LifecycleNotifier : public virtual WillBeGarbageCollectedMixin {
 public:
     typedef LifecycleObserver<T> Observer;
     typedef T Context;
@@ -53,7 +55,11 @@ public:
     virtual void addObserver(Observer*);
     virtual void removeObserver(Observer*);
 
-    virtual void trace(Visitor*) { }
+    virtual void trace(Visitor* visitor)
+    {
+        visitor->trace(m_context);
+        visitor->trace(m_observers);
+    }
 
     bool isIteratingOverObservers() const { return m_iterating != IteratingNone; }
 
@@ -65,7 +71,7 @@ protected:
     {
     }
 
-    Context* context() const { return m_context; }
+    Context* context() const { return m_context.get(); }
 
     enum IterationType {
         IteratingNone,
@@ -79,20 +85,20 @@ protected:
     IterationType m_iterating;
 
 private:
-    typedef HashSet<Observer*> ObserverSet;
+    typedef WillBeHeapHashSet<RawPtrWillBeMember<Observer>> ObserverSet;
 
     ObserverSet m_observers;
-    Context* m_context;
+    RawPtrWillBeWeakMember<Context> m_context;
     bool m_didCallContextDestroyed;
 };
 
 template<typename T>
 inline LifecycleNotifier<T>::~LifecycleNotifier()
 {
+#if !ENABLE(OILPAN)
     // FIXME: Enable the following ASSERT. Also see a FIXME in Document::detach().
     // ASSERT(!m_observers.size() || m_didCallContextDestroyed);
 
-#if !ENABLE(OILPAN)
     TemporaryChange<IterationType> scope(this->m_iterating, IteratingOverAll);
     for (Observer* observer : m_observers) {
         ASSERT(observer->lifecycleContext() == m_context);
@@ -109,6 +115,12 @@ inline void LifecycleNotifier<T>::notifyContextDestroyed()
         return;
 
     TemporaryChange<IterationType> scope(this->m_iterating, IteratingOverAll);
+#if ENABLE(OILPAN)
+    for (Observer* observer : m_observers) {
+        ASSERT(observer->lifecycleContext() == m_context);
+        observer->contextDestroyed();
+    }
+#else
     Vector<Observer*> snapshotOfObservers;
     copyToVector(m_observers, snapshotOfObservers);
     for (Observer* observer : snapshotOfObservers) {
@@ -122,6 +134,7 @@ inline void LifecycleNotifier<T>::notifyContextDestroyed()
             observer->contextDestroyed();
         }
     }
+#endif
     m_didCallContextDestroyed = true;
 }
 
@@ -135,6 +148,9 @@ inline void LifecycleNotifier<T>::addObserver(typename LifecycleNotifier<T>::Obs
 template<typename T>
 inline void LifecycleNotifier<T>::removeObserver(typename LifecycleNotifier<T>::Observer* observer)
 {
+#if ENABLE(OILPAN)
+    RELEASE_ASSERT(m_iterating != IteratingOverAll);
+#endif
     m_observers.remove(observer);
 }