Replace IDBPendingTransactionMonitor with end-of-recursion-scope tasks

Source/modules/indexeddb/IDBTransaction.cpp

Index: Source/modules/indexeddb/IDBTransaction.cpp
diff --git a/Source/modules/indexeddb/IDBTransaction.cpp b/Source/modules/indexeddb/IDBTransaction.cpp
index a3f3ea5cedab85656d93bd8ae26666282b879839..71eaaa13de77a77f28e20f965b72930678f4b174 100644
--- a/Source/modules/indexeddb/IDBTransaction.cpp
+++ b/Source/modules/indexeddb/IDBTransaction.cpp
@@ -59,6 +59,30 @@ IDBTransaction* IDBTransaction::create(ScriptState* scriptState, int64_t id, IDB
     return transaction;
 }
 
+namespace {
+
+class DeactivateTransactionTask : public V8PerIsolateData::EndOfScopeTask {
+public:
+    static PassOwnPtr<DeactivateTransactionTask> create(IDBTransaction* transaction)
+    {
+        return adoptPtr(new DeactivateTransactionTask(transaction));
+    }
+
+    void Run() override
+    {
+        m_transaction->setActive(false);
+        m_transaction.clear();
+    }
+
+private:
+    explicit DeactivateTransactionTask(IDBTransaction* transaction)
+        : m_transaction(transaction) { }
+
+    Persistent<IDBTransaction> m_transaction;
+};
+
+} // namespace
+
 IDBTransaction::IDBTransaction(ScriptState* scriptState, int64_t id, const Vector<String>& objectStoreNames, WebIDBTransactionMode mode, IDBDatabase* db, IDBOpenDBRequest* openDBRequest, const IDBDatabaseMetadata& previousMetadata)
     : ActiveDOMObject(scriptState->executionContext())
     , m_id(id)
@@ -77,7 +101,7 @@ IDBTransaction::IDBTransaction(ScriptState* scriptState, int64_t id, const Vecto
     }
 
     if (m_state == Active)
-        V8PerIsolateData::from(scriptState->isolate())->ensureIDBPendingTransactionMonitor()->addNewTransaction(*this);
+        V8PerIsolateData::from(scriptState->isolate())->addEndOfScopeTask(DeactivateTransactionTask::create(this));
     m_database->transactionCreated(this);
 }