Add rtc_event_log_unittest_helper.h to relevant BUILD.gn

webrtc/logging/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("../webrtc.gni")
 import("//third_party/protobuf/proto_library.gni")
@@ skipping 89 matching lines @@
       "../rtc_base:rtc_base_approved",
     ]
   }
 
   if (rtc_include_tests) {
     rtc_source_set("rtc_event_log_tests") {
       testonly = true
       sources = [
         "rtc_event_log/rtc_event_log_unittest.cc",
         "rtc_event_log/rtc_event_log_unittest_helper.cc",
+        "rtc_event_log/rtc_event_log_unittest_helper.h",
       ]
       deps = [
         ":rtc_event_log_impl",
         ":rtc_event_log_parser",
         "../call",
         "../modules/audio_coding:audio_network_adaptor",
         "../modules/remote_bitrate_estimator:remote_bitrate_estimator",
         "../modules/rtp_rtcp",
         "../rtc_base:rtc_base_approved",
         "../rtc_base:rtc_base_tests_utils",
@@ skipping 65 matching lines @@
         "../rtc_base:rtc_base_approved",
         "//third_party/gflags",
       ]
       if (!build_with_chromium && is_clang) {
         # Suppress warnings from the Chromium Clang plugin (bugs.webrtc.org/163).
         suppressed_configs += [ "//build/config/clang:find_bad_constructs" ]
       }
     }
   }
 }