Oilpan: avoid InjectedScriptManager::CallbackData-induced leaks.

Source/core/inspector/InjectedScriptManager.h

Index: Source/core/inspector/InjectedScriptManager.h
diff --git a/Source/core/inspector/InjectedScriptManager.h b/Source/core/inspector/InjectedScriptManager.h
index 2a27e2107831242bc0d2e0ef89b30836221c08e4..c591be8e6556965c576c40ab409e93bc9219f940 100644
--- a/Source/core/inspector/InjectedScriptManager.h
+++ b/Source/core/inspector/InjectedScriptManager.h
@@ -47,10 +47,17 @@ class InjectedScriptManager : public NoBaseWillBeGarbageCollectedFinalized<Injec
     WTF_MAKE_NONCOPYABLE(InjectedScriptManager);
     WTF_MAKE_FAST_ALLOCATED_WILL_BE_REMOVED(InjectedScriptManager);
 public:
-    struct CallbackData {
+    class CallbackData final : public NoBaseWillBeGarbageCollectedFinalized<CallbackData> {
+    public:
+        static PassOwnPtrWillBeRawPtr<CallbackData> create(InjectedScriptManager*);
+        void dispose();
+        DECLARE_TRACE();
+
         ScopedPersistent<v8::Object> handle;
-        RefPtrWillBePersistent<InjectedScriptHost> host;
-        InjectedScriptManager* injectedScriptManager;
+        RefPtrWillBeMember<InjectedScriptHost> host;
+        RawPtrWillBeMember<InjectedScriptManager> injectedScriptManager;
+    private:
+        explicit CallbackData(InjectedScriptManager*);
     };
 
     static PassOwnPtrWillBeRawPtr<InjectedScriptManager> createForPage();
@@ -94,7 +101,7 @@ private:
     InspectedStateAccessCheck m_inspectedStateAccessCheck;
     typedef HashMap<RefPtr<ScriptState>, int> ScriptStateToId;
     ScriptStateToId m_scriptStateToId;
-    HashSet<OwnPtr<CallbackData> > m_callbackDataSet;
+    WillBeHeapHashSet<OwnPtrWillBeMember<CallbackData>> m_callbackDataSet;
     bool m_customObjectFormatterEnabled;
 };