drive: Return cancel closure from FileSystem::GetFileContent

chrome/browser/chromeos/drive/sync_client.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_CHROMEOS_DRIVE_SYNC_CLIENT_H_
 #define CHROME_BROWSER_CHROMEOS_DRIVE_SYNC_CLIENT_H_
 
 #include <map>
 #include <string>
 #include <vector>
@@ skipping 83 matching lines @@
   // States of sync tasks.
   enum SyncState {
     PENDING,
     RUNNING,
   };
 
   struct SyncTask {
     SyncTask();
     ~SyncTask();
     SyncState state;
-    base::Closure task;
+    base::Callback<base::Closure()> task;
     bool should_run_again;
     base::Closure cancel_closure;
   };
 
   typedef std::map<std::pair<SyncType, std::string>, SyncTask> SyncTasks;
 
   // Adds a FETCH task.
   void AddFetchTaskInternal(const std::string& local_id,
                             const base::TimeDelta& delay);
 
@@ skipping 10 matching lines @@
   // Called when a task is ready to start.
   void StartTask(const SyncTasks::key_type& key);
 
   // Called when the local IDs of files in the backlog are obtained.
   void OnGetLocalIdsOfBacklog(const std::vector<std::string>* to_fetch,
                               const std::vector<std::string>* to_update);
 
   // Adds fetch tasks.
   void AddFetchTasks(const std::vector<std::string>* local_ids);
 
-  // Used as GetFileContentInitializedCallback.
-  void OnGetFileContentInitialized(
-      FileError error,
-      scoped_ptr<ResourceEntry> entry,
-      const base::FilePath& local_cache_file_path,
-      const base::Closure& cancel_download_closure);
-
   // Erases the task and returns true if task is completed.
   bool OnTaskComplete(SyncType type, const std::string& local_id);
 
   // Called when the file for |local_id| is fetched.
   void OnFetchFileComplete(const std::string& local_id,
                            FileError error,
                            const base::FilePath& local_path,
                            scoped_ptr<ResourceEntry> entry);
 
   // Called when the entry is updated.
@@ skipping 27 matching lines @@
   // invalidate its weak pointers before any other members are destroyed.
   base::WeakPtrFactory<SyncClient> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(SyncClient);
 };
 
 }  // namespace internal
 }  // namespace drive
 
 #endif  // CHROME_BROWSER_CHROMEOS_DRIVE_SYNC_CLIENT_H_