chromeos: Add DriveFileSystem::Pin/Unpin

chrome/browser/chromeos/drive/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_DRIVE_FILE_SYSTEM_INTERFACE_H_
 #define CHROME_BROWSER_CHROMEOS_DRIVE_DRIVE_FILE_SYSTEM_INTERFACE_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 264 matching lines @@
   // Creates a file at |file_path|. If the flag |is_exclusive| is true, an
   // error is raised when a file already exists at the path. It is
   // an error if a directory or a hosted document is already present at the
   // path, or the parent directory of the path is not present yet.
   //
   // |callback| must not be null.
   virtual void CreateFile(const base::FilePath& file_path,
                           bool is_exclusive,
                           const FileOperationCallback& callback) = 0;
 
+  // Pins a file at |file_path|.
+  //
+  // |callback| must not be null.
+  virtual void Pin(const base::FilePath& file_path,
+                   const FileOperationCallback& callback) = 0;
+
+  // Unpins a file at |file_path|.
+  //
+  // |callback| must not be null.
+  virtual void Unpin(const base::FilePath& file_path,
+                     const FileOperationCallback& callback) = 0;
+
   // Gets |file_path| from the file system. The file entry represented by
   // |file_path| needs to be present in in-memory representation of the file
   // system in order to be retrieved. If the file is not cached, the file
   // will be downloaded through GData API or Drive V2 API.
   //
   // |callback| must not be null.
   virtual void GetFileByPath(const base::FilePath& file_path,
                              const GetFileCallback& callback) = 0;
 
   // Gets a file by the given |resource_id| from the Drive server. Used for
@@ skipping 125 matching lines @@
   virtual void GetMetadata(
       const GetFilesystemMetadataCallback& callback) = 0;
 
   // Reloads the file system feeds from the server.
   virtual void Reload() = 0;
 };
 
 }  // namespace drive
 
 #endif  // CHROME_BROWSER_CHROMEOS_DRIVE_DRIVE_FILE_SYSTEM_INTERFACE_H_