Commit History transaction when app is backgrounded on iOS

components/history/core/browser/history_backend.h

 // Copyright (c) 2012 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 COMPONENTS_HISTORY_CORE_BROWSER_HISTORY_BACKEND_H_
 #define COMPONENTS_HISTORY_CORE_BROWSER_HISTORY_BACKEND_H_
 
 #include <set>
 #include <string>
 #include <utility>
@@ skipping 173 matching lines @@
   // |force_fail| can be set during unittests to unconditionally fail to init.
   void Init(const std::string& languages,
             bool force_fail,
             const HistoryDatabaseParams& history_database_params);
 
   // Notification that the history system is shutting down. This will break
   // the refs owned by the delegate and any pending transaction so it will
   // actually be deleted.
   void Closing();
 
+#if defined(OS_IOS)
+  // Persists any in-flight state, without actually shutting down the history
+  // system. This is intended for use when the application is backgrounded.
+  void PersistState();
+#endif
+
   void ClearCachedDataForContextID(ContextID context_id);
 
   // Navigation ----------------------------------------------------------------
 
   // |request.time| must be unique with high probability.
   void AddPage(const HistoryAddPageArgs& request);
   virtual void SetPageTitle(const GURL& url, const base::string16& title);
   void AddPageNoVisitForBookmark(const GURL& url, const base::string16& title);
   void UpdateWithPageEndTime(ContextID context_id,
                              int nav_entry_id,
@@ skipping 613 matching lines @@
 
   // List of observers
   ObserverList<HistoryBackendObserver> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(HistoryBackend);
 };
 
 }  // namespace history
 
 #endif  // COMPONENTS_HISTORY_CORE_BROWSER_HISTORY_BACKEND_H_