[fsp] Add support for opening files.

chrome/browser/chromeos/file_system_provider/provided_file_system_interface.h

 // Copyright 2014 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_FILE_SYSTEM_PROVIDER_PROVIDED_FILE_SYSTEM_INTERFACE_H_
 #define CHROME_BROWSER_CHROMEOS_FILE_SYSTEM_PROVIDER_PROVIDED_FILE_SYSTEM_INTERFACE_H_
 
 #include "webkit/browser/fileapi/async_file_util.h"
 
 class EventRouter;
 
 namespace base {
 class FilePath;
 }  // namespace base
 
 namespace chromeos {
 namespace file_system_provider {
 
 class ProvidedFileSystemInfo;
 class RequestManager;
 
 // Interface for a provided file system. Acts as a proxy between providers
 // and clients.
 // TODO(mtomasz): Add more methods once implemented.
 class ProvidedFileSystemInterface {
  public:
+  // Mode of opening a file. Used by OpenFile().
+  enum OpenFileMode { OPEN_FILE_MODE_READ, OPEN_FILE_MODE_WRITE };
+
   virtual ~ProvidedFileSystemInterface() {}
 
   // Requests unmounting of the file system. The callback is called when the
   // request is accepted or rejected, with an error code.
   virtual void RequestUnmount(
       const fileapi::AsyncFileUtil::StatusCallback& callback) = 0;
 
   // Requests metadata of the passed |entry_path|. It can be either a file
   // or a directory.
   virtual void GetMetadata(
       const base::FilePath& entry_path,
       const fileapi::AsyncFileUtil::GetFileInfoCallback& callback) = 0;
   // Requests enumerating entries from the passed |directory_path|. The callback
   // can be called multiple times until either an error is returned or the
   // has_more field is set to false.
   virtual void ReadDirectory(
       const base::FilePath& directory_path,
       const fileapi::AsyncFileUtil::ReadDirectoryCallback& callback) = 0;
 
+  // Requests opening a file at |file_path|. If |create| is set to true, it will
+  // create a file and return succes in case it didn't exist.
+  virtual void OpenFile(
+      const base::FilePath& file_path,
+      OpenFileMode mode,
+      bool create,
+      const fileapi::AsyncFileUtil::StatusCallback& callback) = 0;
+
   // Returns a provided file system info for this file system.
   virtual const ProvidedFileSystemInfo& GetFileSystemInfo() const = 0;
 
   // Returns a request manager for the file system.
   virtual RequestManager* GetRequestManager() = 0;
 };
 
 }  // namespace file_system_provider
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_FILE_SYSTEM_PROVIDER_PROVIDED_FILE_SYSTEM_INTERFACE_H_