Port HistoryService::ScheduleDBTask to CancelableTaskTracker

chrome/browser/history/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 CHROME_BROWSER_HISTORY_HISTORY_BACKEND_H_
 #define CHROME_BROWSER_HISTORY_HISTORY_BACKEND_H_
 
 #include <set>
 #include <string>
 #include <utility>
 #include <vector>
 
 #include "base/containers/mru_cache.h"
 #include "base/files/file_path.h"
 #include "base/gtest_prod_util.h"
 #include "base/memory/memory_pressure_listener.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/task/cancelable_task_tracker.h"
 #include "chrome/browser/history/expire_history_backend.h"
 #include "chrome/browser/history/history_database.h"
 #include "chrome/browser/history/history_marshaling.h"
 #include "chrome/browser/history/history_types.h"
 #include "chrome/browser/history/thumbnail_database.h"
 #include "chrome/browser/history/visit_tracker.h"
 #include "components/history/core/browser/keyword_id.h"
 #include "sql/init_status.h"
 
 class TestingProfile;
@@ skipping 11 matching lines @@
 struct DownloadRow;
 
 // The maximum number of icons URLs per page which can be stored in the
 // thumbnail database.
 static const size_t kMaxFaviconsPerPage = 8;
 
 // The maximum number of bitmaps for a single icon URL which can be stored in
 // the thumbnail database.
 static const size_t kMaxFaviconBitmapsPerIconURL = 8;
 
+class QueuedHistoryDBTask {
+ public:
+  QueuedHistoryDBTask(
+      scoped_refptr<HistoryDBTask> task,
+      scoped_refptr<base::SingleThreadTaskRunner> origin_loop,
+      const base::CancelableTaskTracker::IsCanceledCallback& is_canceled);
+  ~QueuedHistoryDBTask();
+
+  bool is_canceled();
+  bool RunOnDBThread(HistoryBackend* backend, HistoryDatabase* db);
+  void DoneRunOnMainThread();
+
+ private:
+  scoped_refptr<HistoryDBTask> task_;
+  scoped_refptr<base::SingleThreadTaskRunner> origin_loop_;
+  base::CancelableTaskTracker::IsCanceledCallback is_canceled_;
+};
+
 // *See the .cc file for more information on the design.*
 //
 // Internal history implementation which does most of the work of the history
 // system. This runs on a background thread (to not block the browser when we
 // do expensive operations) and is NOT threadsafe, so it must only be called
 // from message handlers on the background thread. Invoking on another thread
 // requires threadsafe refcounting.
 //
 // Most functions here are just the implementations of the corresponding
 // functions in the history service. These functions are not documented
@@ skipping 254 matching lines @@
   void QuerySearchTerms(scoped_refptr<QueryRequest> request,
                         const std::vector<SearchRow::ColumnID>& projections,
                         const std::string& selection,
                         const std::vector<base::string16>& selection_args,
                         const std::string& sort_order);
 
 #endif  // defined(OS_ANDROID)
 
   // Generic operations --------------------------------------------------------
 
-  void ProcessDBTask(scoped_refptr<HistoryDBTaskRequest> request);
+  void ProcessDBTask(
+      scoped_refptr<HistoryDBTask> task,
+      scoped_refptr<base::SingleThreadTaskRunner> origin_loop,
+      const base::CancelableTaskTracker::IsCanceledCallback& is_canceled);
 
   virtual bool GetAllTypedURLs(URLRows* urls);
 
   virtual bool GetVisitsForURL(URLID id, VisitVector* visits);
 
   // Fetches up to |max_visits| most recent visits for the passed URL.
   virtual bool GetMostRecentVisitsForURL(URLID id,
                                          int max_visits,
                                          VisitVector* visits);
 
@@ skipping 371 matching lines @@
   // redirects.
   void SendFaviconChangedNotificationForPageAndRedirects(
       const GURL& page_url);
 
   // Generic stuff -------------------------------------------------------------
 
   // Processes the next scheduled HistoryDBTask, scheduling this method
   // to be invoked again if there are more tasks that need to run.
   void ProcessDBTaskImpl();
 
-  // Release all tasks in history_db_tasks_ and clears it.
-  void ReleaseDBTasks();
-
   virtual void BroadcastNotifications(
       int type,
       scoped_ptr<HistoryDetails> details) OVERRIDE;
   virtual void NotifySyncURLsModified(URLRows* rows) OVERRIDE;
   virtual void NotifySyncURLsDeleted(bool all_history,
                                      bool expired,
                                      URLRows* rows) OVERRIDE;
 
   // Deleting all history ------------------------------------------------------
 
@@ skipping 73 matching lines @@
   base::MessageLoop* backend_destroy_message_loop_;
   base::Closure backend_destroy_task_;
 
   // Tracks page transition types.
   VisitTracker tracker_;
 
   // A boolean variable to track whether we have already purged obsolete segment
   // data.
   bool segment_queried_;
 
-  // HistoryDBTasks to run. Be sure to AddRef when adding, and Release when
-  // done.
-  std::list<HistoryDBTaskRequest*> db_task_requests_;
+  // List of QueuedHistoryDBTasks to run;
+  std::list<QueuedHistoryDBTask> queued_history_db_tasks_;
 
   // Used to determine if a URL is bookmarked; may be NULL.
   //
   // Use GetHistoryClient to access this, which makes sure the bookmarks are
   // loaded before returning.
   HistoryClient* history_client_;
 
 #if defined(OS_ANDROID)
   // Used to provide the Android ContentProvider APIs.
   scoped_ptr<AndroidProviderBackend> android_provider_backend_;
@@ skipping 11 matching lines @@
 
   // Listens for the system being under memory pressure.
   scoped_ptr<base::MemoryPressureListener> memory_pressure_listener_;
 
   DISALLOW_COPY_AND_ASSIGN(HistoryBackend);
 };
 
 }  // namespace history
 
 #endif  // CHROME_BROWSER_HISTORY_HISTORY_BACKEND_H_