Reland of Enable GN check for webrtc/base

webrtc/system_wrappers/BUILD.gn

 # 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.
 
 if (is_android) {
   import("//build/config/android/config.gni")
   import("//build/config/android/rules.gni")
 }
 import("../webrtc.gni")
 
 rtc_static_library("system_wrappers") {
   sources = [
     "include/aligned_array.h",
     "include/aligned_malloc.h",
     "include/atomic32.h",
     "include/clock.h",
     "include/cpu_info.h",
     "include/event_wrapper.h",
     "include/file_wrapper.h",
     "include/fix_interlocked_exchange_pointer_win.h",
     "include/ntp_time.h",
     "include/rtp_to_ntp_estimator.h",
     "include/rw_lock_wrapper.h",
     "include/sleep.h",
     "include/static_instance.h",
-    "include/stringize_macros.h",
     "include/timestamp_extrapolator.h",
     "include/trace.h",
     "source/aligned_malloc.cc",
     "source/atomic32_win.cc",
     "source/clock.cc",
     "source/cpu_features.cc",
     "source/cpu_info.cc",
     "source/event.cc",
     "source/event_timer_posix.cc",
     "source/event_timer_posix.h",
@@ skipping 163 matching lines @@
     testonly = true
     sources = [
       "source/aligned_array_unittest.cc",
       "source/aligned_malloc_unittest.cc",
       "source/clock_unittest.cc",
       "source/event_timer_posix_unittest.cc",
       "source/metrics_default_unittest.cc",
       "source/metrics_unittest.cc",
       "source/ntp_time_unittest.cc",
       "source/rtp_to_ntp_estimator_unittest.cc",
-      "source/stringize_macros_unittest.cc",
     ]
     configs += [ "//build/config/compiler:no_size_t_to_int_warning" ]
 
     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" ]
     }
 
     deps = [
       ":metrics_default",
       ":system_wrappers",
       "..:webrtc_common",
       "../base:rtc_base_approved",
       "../test:test_main",
       "//testing/gtest",
     ]
 
     if (is_android) {
       deps += [ "//testing/android/native_test:native_test_support" ]
 
       shard_timeout = 900
     }
   }
 }