[fsp] Add support for truncating files.

chrome/chrome_browser_chromeos.gypi

 # 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.
 
 {
   'targets': [
     {
       'target_name': 'browser_chromeos',
       'type': 'static_library',
@@ skipping 403 matching lines @@
         'browser/chromeos/file_system_provider/operations/move_entry.cc',
         'browser/chromeos/file_system_provider/operations/move_entry.h',
         'browser/chromeos/file_system_provider/operations/open_file.cc',
         'browser/chromeos/file_system_provider/operations/open_file.h',
         'browser/chromeos/file_system_provider/operations/operation.cc',
         'browser/chromeos/file_system_provider/operations/operation.h',
         'browser/chromeos/file_system_provider/operations/read_directory.cc',
         'browser/chromeos/file_system_provider/operations/read_directory.h',
         'browser/chromeos/file_system_provider/operations/read_file.cc',
         'browser/chromeos/file_system_provider/operations/read_file.h',
+        'browser/chromeos/file_system_provider/operations/truncate.cc',
+        'browser/chromeos/file_system_provider/operations/truncate.h',
         'browser/chromeos/file_system_provider/operations/unmount.cc',
         'browser/chromeos/file_system_provider/operations/unmount.h',
         'browser/chromeos/file_system_provider/provided_file_system.cc',
         'browser/chromeos/file_system_provider/provided_file_system.h',
         'browser/chromeos/file_system_provider/provided_file_system_info.cc',
         'browser/chromeos/file_system_provider/provided_file_system_info.h',
         'browser/chromeos/file_system_provider/provided_file_system_interface.cc',
         'browser/chromeos/file_system_provider/provided_file_system_interface.h',
         'browser/chromeos/file_system_provider/request_manager.cc',
         'browser/chromeos/file_system_provider/request_manager.h',
@@ skipping 749 matching lines @@
         'browser/chromeos/attestation/attestation_signed_data.proto',
       ],
       'variables': {
         'proto_in_dir': 'browser/chromeos/attestation',
         'proto_out_dir': 'chrome/browser/chromeos/attestation',
       },
       'includes': [ '../build/protoc.gypi' ]
     },
   ],
 }