Remove all references to GYP

webrtc/stats/stats.gyp

-# Copyright (c) 2016 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': [
-    {
-      # GN version: webrtc/stats:rtc_stats
-      'target_name': 'rtc_stats',
-      'type': 'static_library',
-      'dependencies': [
-        '<(webrtc_root)/api/api.gyp:rtc_stats_api',
-        '<(webrtc_root)/base/base.gyp:rtc_base_approved',
-      ],
-      'sources': [
-        'rtcstats.cc',
-        'rtcstats_objects.cc',
-        'rtcstatsreport.cc',
-      ],
-    },
-  ],
-}