[fsp] Add support for creating 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 <string>
 
 #include "base/callback.h"
@@ skipping 91 matching lines @@
 
   // Requests creating a directory. If |recursive| is passed, then all non
   // existing directories on the path will be created. If |exclusive| is true,
   // then creating the directory will fail, if it already exists.
   virtual void CreateDirectory(
       const base::FilePath& directory_path,
       bool exclusive,
       bool recursive,
       const fileapi::AsyncFileUtil::StatusCallback& callback) = 0;
 
+  // Requests creating a file. If the entry already exists, then the
+  // FILE_ERROR_EXISTS error must be returned.
+  virtual void CreateFile(
+      const base::FilePath& file_path,
+      const fileapi::AsyncFileUtil::StatusCallback& callback) = 0;
+
   // Requests deleting a directory. If |recursive| is passed and the entry is
   // a directory, then all contents of it (recursively) will be deleted too.
   virtual void DeleteEntry(
       const base::FilePath& entry_path,
       bool recursive,
       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;
 
   // Returns a weak pointer to this object.
   virtual base::WeakPtr<ProvidedFileSystemInterface> GetWeakPtr() = 0;
 };
 
 }  // namespace file_system_provider
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_FILE_SYSTEM_PROVIDER_PROVIDED_FILE_SYSTEM_INTERFACE_H_