Delete unused class AsyncFile.

webrtc/base/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.
 
 import("//build/config/crypto.gni")
 import("//build/config/ui.gni")
@@ skipping 370 matching lines @@
 
   public_configs = [
     ":openssl_config",
     ":rtc_base_config",
   ]
 
   all_dependent_configs = [ ":rtc_base_all_dependent_config" ]
 
   sources = [
     "applefilesystem.mm",
-    "asyncfile.cc",
-    "asyncfile.h",
     "asyncinvoker-inl.h",
     "asyncinvoker.cc",
     "asyncinvoker.h",
     "asyncpacketsocket.cc",
     "asyncpacketsocket.h",
     "asyncresolverinterface.cc",
     "asyncresolverinterface.h",
     "asyncsocket.cc",
     "asyncsocket.h",
     "asynctcpsocket.cc",
@@ skipping 365 matching lines @@
 
     deps = [
       "//base:base_java",
     ]
 
     data = [
       "//webrtc/build/android/test_runner.py",
     ]
   }
 }