Cleanup: Get rid of OS_WIN/OS_POSIX ifdefs from MojoApplication

base/BUILD.gn

 # Copyright (c) 2013 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("//build/config/ui.gni")
 
 if (is_android) {
   import("//build/config/android/rules.gni")
 }
 
@@ skipping 204 matching lines @@
     "files/file_util_posix.cc",
     "files/file_util_proxy.cc",
     "files/file_util_proxy.h",
     "files/file_util_win.cc",
     "files/important_file_writer.cc",
     "files/important_file_writer.h",
     "files/memory_mapped_file.cc",
     "files/memory_mapped_file.h",
     "files/memory_mapped_file_posix.cc",
     "files/memory_mapped_file_win.cc",
+    "files/platform_file.h",
     "files/scoped_file.cc",
     "files/scoped_file.h",
     "files/scoped_temp_dir.cc",
     "files/scoped_temp_dir.h",
     "float_util.h",
     "format_macros.h",
     "gtest_prod_util.h",
     "guid.cc",
     "guid.h",
     "guid_posix.cc",
@@ skipping 1216 matching lines @@
   # GYP: //base.gyp:base_unittests_apk
   unittest_apk("base_unittests_apk") {
     deps = [
       ":base_java",
       ":base_java_unittest_support",
       ":base_unittests",
     ]
     unittests_dep = ":base_unittests"
   }
 }