Remove .def files from GYP and GN in webrtc/base

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 403 matching lines @@
         "libdbusglibsymboltable.cc",
         "libdbusglibsymboltable.h",
         "linuxfdwalk.c",
         "linuxfdwalk.h",
       ]
     }
 
     if (is_posix) {
       sources += [
         "latebindingsymboltable.cc",
-        "latebindingsymboltable.cc.def",
         "latebindingsymboltable.h",
-        "latebindingsymboltable.h.def",
         "posix.cc",
         "posix.h",
       ]
     }
 
     if (is_mac) {
       sources += [
         "macasyncsocket.cc",
         "macasyncsocket.h",
         "maccocoasocketserver.h",
@@ skipping 200 matching lines @@
       "objc/RTCUIApplication.mm",
     ]
   }
 }
 
 source_set("gtest_prod") {
   sources = [
     "gtest_prod_util.h",
   ]
 }