GN: Tighten up test target visibility + refactorings

webrtc/modules/bitrate_controller/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.
 
 import("../../webrtc.gni")
 
@@ skipping 28 matching lines @@
   deps = [
     "../../base:rtc_base_approved",
     "../../system_wrappers",
     "../rtp_rtcp",
   ]
 }
 
 if (rtc_include_tests) {
   rtc_source_set("bitrate_controller_unittests") {
     testonly = true
+    if (!is_android && !is_ios) {  # Generated targets makes this check break.
+      visibility = [ "//webrtc/modules:modules_unittests" ]
+    }
     sources = [
       "bitrate_controller_unittest.cc",
       "send_side_bandwidth_estimation_unittest.cc",
     ]
     deps = [
       ":bitrate_controller",
       "../../test:field_trial",
       "../../test:test_support",
       "../remote_bitrate_estimator:remote_bitrate_estimator",
       "//testing/gmock",
     ]
     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" ]
     }
   }
 }