FileWrapper[Impl] modifications and actually remove the "Impl" class.

webrtc/system_wrappers/BUILD.gn

 # Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
 #
 # Use of this source code is governed by a BSD-style license
 # that can be found in the LICENSE file in the root of the source
 # tree. An additional intellectual property rights grant can be found
 # in the file PATENTS.  All contributing project authors may
 # be found in the AUTHORS file in the root of the source tree.
 
 if (is_android) {
   import("//build/config/android/config.gni")
@@ skipping 38 matching lines @@
     "source/condition_variable_event_win.h",
     "source/cpu_features.cc",
     "source/cpu_info.cc",
     "source/data_log_c.cc",
     "source/event.cc",
     "source/event_timer_posix.cc",
     "source/event_timer_posix.h",
     "source/event_timer_win.cc",
     "source/event_timer_win.h",
     "source/file_impl.cc",
-    "source/file_impl.h",
     "source/logging.cc",
     "source/rtp_to_ntp.cc",
     "source/rw_lock.cc",
     "source/rw_lock_posix.cc",
     "source/rw_lock_posix.h",
     "source/rw_lock_win.cc",
     "source/rw_lock_win.h",
     "source/rw_lock_winxp_win.cc",
     "source/rw_lock_winxp_win.h",
     "source/sleep.cc",
@@ skipping 167 matching lines @@
       ":system_wrappers",
       "../test:test_support_main",
       "//testing/gtest",
     ]
 
     if (is_android) {
       deps += [ "//testing/android/native_test:native_test_support" ]
     }
   }
 }