drive: Change FileCache::GetCacheEntry's return type to FileError

chrome/browser/chromeos/drive/file_system_interface.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_FILE_SYSTEM_INTERFACE_H_
 #define CHROME_BROWSER_CHROMEOS_DRIVE_FILE_SYSTEM_INTERFACE_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 107 matching lines @@
 // Used to get filesystem metadata.
 typedef base::Callback<void(const FileSystemMetadata&)>
     GetFilesystemMetadataCallback;
 
 // Used to mark cached files mounted.
 typedef base::Callback<void(FileError error,
                             const base::FilePath& file_path)>
     MarkMountedCallback;
 
 // Callback for GetCacheEntry.
-// |success| indicates if the operation was successful.
-// |cache_entry| is the obtained cache entry.
-typedef base::Callback<void(bool success, const FileCacheEntry& cache_entry)>
+typedef base::Callback<void(FileError error, const FileCacheEntry& cache_entry)>
     GetCacheEntryCallback;
 
 // Used to get file path.
 typedef base::Callback<void(FileError error, const base::FilePath& file_path)>
     GetFilePathCallback;
 
 // The mode of opening a file.
 enum OpenMode {
   // Open the file if exists. If not, failed.
   OPEN_FILE,
@@ skipping 294 matching lines @@
   virtual void Reset(const FileOperationCallback& callback) = 0;
 
   // Finds a path of an entry (a file or a directory) by |resource_id|.
   virtual void GetPathFromResourceId(const std::string& resource_id,
                                      const GetFilePathCallback& callback) = 0;
 };
 
 }  // namespace drive
 
 #endif  // CHROME_BROWSER_CHROMEOS_DRIVE_FILE_SYSTEM_INTERFACE_H_