mandoline filesystem: Rewrite using base::File.

components/filesystem/BUILD.gn

 # 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.
 
 import("//third_party/mojo/src/mojo/public/mojo_application.gni")
 
 mojo_native_application("filesystem") {
   sources = [
     "directory_impl.cc",
     "directory_impl.h",
     "file_impl.cc",
     "file_impl.h",
     "file_system_impl.cc",
     "file_system_impl.h",
-    "futimens.h",
-    "futimens_android.cc",
     "main.cc",
-    "shared_impl.cc",
-    "shared_impl.h",
     "util.cc",
     "util.h",
   ]
 
   deps = [
     "//base",
     "//components/filesystem/public/interfaces",
     "//mojo/application/public/cpp",
     "//mojo/common",
     "//mojo/environment:chromium",
     "//third_party/mojo/src/mojo/public/cpp/bindings",
     "//third_party/mojo/src/mojo/public/cpp/system",
   ]
 }
 
 mojo_native_application("apptests") {
-  output_name = "files_apptests"
+  output_name = "filesystem_apptests"
 
   testonly = true
 
   sources = [
     "directory_impl_unittest.cc",
     "file_impl_unittest.cc",
     "files_test_base.cc",
     "files_test_base.h",
   ]
 
   deps = [
     "//base",
     "//components/filesystem/public/interfaces",
     "//mojo/application/public/cpp:test_support",
     "//third_party/mojo/src/mojo/public/cpp/bindings",
   ]
 }