Fix all -Wnon-virtual-dtor warnings.

webrtc/libjingle/xmpp/xmpp.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', ],
   'targets': [
     {
       'target_name': 'rtc_xmpp',
       'type': 'static_library',
       'dependencies': [
         '<(webrtc_root)/base/base.gyp:rtc_base',
         '<(webrtc_root)/libjingle/xmllite/xmllite.gyp:rtc_xmllite',
       ],
       'defines': [
         'FEATURE_ENABLE_SSL',
       ],
-      'cflags_cc!': [
-        '-Wnon-virtual-dtor',
-      ],
       'sources': [
         'asyncsocket.h',
         'chatroommodule.h',
         'chatroommoduleimpl.cc',
         'constants.cc',
         'constants.h',
         'discoitemsquerytask.cc',
         'discoitemsquerytask.h',
         'hangoutpubsubclient.cc',
         'hangoutpubsubclient.h',
@@ skipping 56 matching lines @@
         'xmppsocket.cc',
         'xmppsocket.h',
         'xmppstanzaparser.cc',
         'xmppstanzaparser.h',
         'xmpptask.cc',
         'xmpptask.h',
         'xmppthread.cc',
         'xmppthread.h',
       ],
       'direct_dependent_settings': {
-        'cflags_cc!': [
-          '-Wnon-virtual-dtor',
-        ],
         'defines': [
           'FEATURE_ENABLE_SSL',
           'FEATURE_ENABLE_VOICEMAIL',
         ],
       },
       'conditions': [
         ['build_expat==1', {
           'dependencies': [
             '<(DEPTH)/third_party/expat/expat.gyp:expat',
           ],
@@ skipping 52 matching lines @@
               'xmpplogintask_unittest.cc',
               'xmppstanzaparser_unittest.cc',
             ],
           },
         },  # target rtc_xmpp_unittest
       ],  # targets
     }],  # include_tests==1
   ],  # conditions
 }