Fix building of bwe_test_logging.cc in gyp and gn builds

webrtc/modules/remote_bitrate_estimator/BUILD.gn

Index: webrtc/modules/remote_bitrate_estimator/BUILD.gn
diff --git a/webrtc/modules/remote_bitrate_estimator/BUILD.gn b/webrtc/modules/remote_bitrate_estimator/BUILD.gn
index c929f3eb889e85ea0e8a7970275a6963aa05836f..98a7c201049f35431a5b3d36d808d152ecfad336 100644
--- a/webrtc/modules/remote_bitrate_estimator/BUILD.gn
+++ b/webrtc/modules/remote_bitrate_estimator/BUILD.gn
@@ -6,6 +6,11 @@
 # in the file PATENTS.  All contributing project authors may
 # be found in the AUTHORS file in the root of the source tree.
 
+declare_args() {
+  # Set this to true to enable BWE test logging.
+  enable_bwe_test_logging = false
+}
+
 source_set("remote_bitrate_estimator") {
   sources = [
     "include/bwe_defines.h",
@@ -41,6 +46,10 @@ source_set("rbe_components") {
     "transport_feedback_adapter.h",
   ]
 
+  if (enable_bwe_test_logging) {
+    sources += [ "test/bwe_test_logging.cc" ]
+  }
+
   configs += [ "../..:common_config" ]
   public_configs = [ "../..:common_inherited_config" ]
   deps = [