Move WEBRTC_BUILD_LIBEVENT definition to base/BUILD.gn and base/base.gyp. This use all_dependent_co…

webrtc/base/base.gyp

 # 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.
 
 {
   'includes': [ '../build/common.gypi', ],
@@ skipping 137 matching lines @@
         ['build_libevent==1', {
           'dependencies': [
             '<(DEPTH)/base/third_party/libevent/libevent.gyp:libevent',
           ],
         }],
         ['enable_libevent==1', {
           'sources': [
             'task_queue_libevent.cc',
             'task_queue_posix.cc',
           ],
+          'defines': [ 'WEBRTC_BUILD_LIBEVENT' ],
+          'all_dependent_settings': {
+            'defines': [ 'WEBRTC_BUILD_LIBEVENT' ]
+          },
         }, {
           # If not libevent, fall back to the other task queues.
           'conditions': [
             ['OS=="mac" or OS=="ios"', {
              'sources': [
                'task_queue_gcd.cc',
                'task_queue_posix.cc',
              ],
             }],
             ['OS=="win"', {
@@ skipping 480 matching lines @@
     },
     {
      'target_name': 'gtest_prod',
       'type': 'static_library',
       'sources': [
         'gtest_prod_util.h',
       ],
     },
   ],
 }