RTCStatsReport: Take ownership of other's stats with TakeMembersFrom

webrtc/stats/BUILD.gn

 # 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.
 
 import("../build/webrtc.gni")
 import("//testing/test.gni")
@@ skipping 19 matching lines @@
     "../api:libjingle_peerconnection",
   ]
 }
 
 if (rtc_include_tests) {
   # GYP version: webrtc/stats/stats.gyp:rtc_stats_unittests
   test("rtc_stats_unittests") {
     testonly = true
     sources = [
       "rtcstats_unittest.cc",
+      "rtcstatsreport_unittest.cc",
     ]
 
     configs += [ "..:common_config" ]
     public_configs = [ "..:common_inherited_config" ]
 
     deps = [
       ":rtc_stats",
       "../base:rtc_base_tests_utils",
       "../system_wrappers:metrics_default",
       "//testing/gmock",
     ]
 
     if (is_android) {
       deps += [ "//testing/android/native_test:native_test_native_code" ]
     }
   }
 }