IndexedDB: Prevent store/index deletion from racing ahead of use

content/browser/indexed_db/indexed_db_transaction.h

 // Copyright (c) 2013 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 CONTENT_BROWSER_INDEXED_DB_INDEXED_DB_TRANSACTION_H_
 #define CONTENT_BROWSER_INDEXED_DB_INDEXED_DB_TRANSACTION_H_
 
 #include <queue>
 #include <set>
 #include <stack>
@@ skipping 31 matching lines @@
 
   // Called by the transaction coordinator when this transaction is unblocked.
   void Start();
 
   indexed_db::TransactionMode mode() const { return mode_; }
   const std::set<int64>& scope() const { return object_store_ids_; }
 
   void ScheduleTask(Operation task) {
     ScheduleTask(IndexedDBDatabase::NORMAL_TASK, task);
   }
-  void ScheduleTask(Operation task, Operation abort_task);
   void ScheduleTask(IndexedDBDatabase::TaskType, Operation task);
+  void ScheduleAbortTask(Operation abort_task);
   void RegisterOpenCursor(IndexedDBCursor* cursor);
   void UnregisterOpenCursor(IndexedDBCursor* cursor);
   void AddPreemptiveEvent() { pending_preemptive_events_++; }
   void DidCompletePreemptiveEvent() {
     pending_preemptive_events_--;
     DCHECK_GE(pending_preemptive_events_, 0);
   }
   IndexedDBBackingStore::Transaction* BackingStoreTransaction() {
     return transaction_.get();
   }
@@ skipping 92 matching lines @@
   // requests are processed before the timer fires, assume the script is
   // unresponsive and abort to unblock the transaction queue.
   base::OneShotTimer<IndexedDBTransaction> timeout_timer_;
 
   Diagnostics diagnostics_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_INDEXED_DB_INDEXED_DB_TRANSACTION_H_