GN: Tighten up test target visibility + refactorings

webrtc/modules/pacing/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 21 matching lines @@
     "../../system_wrappers",
     "../remote_bitrate_estimator",
     "../rtp_rtcp",
     "../utility",
   ]
 }
 
 if (rtc_include_tests) {
   rtc_source_set("pacing_unittests") {
     testonly = true
+    if (!is_android && !is_ios) {  # Generated targets makes this check break.
+      visibility = [ "//webrtc/modules:modules_unittests" ]
+    }
     sources = [
       "alr_detector_unittest.cc",
       "bitrate_prober_unittest.cc",
       "paced_sender_unittest.cc",
       "packet_router_unittest.cc",
     ]
     deps = [
       ":pacing",
       "../../base:rtc_base_approved",
       "../../base:rtc_base_tests_utils",
       "../../system_wrappers:system_wrappers",
       "../../test:test_support",
       "../rtp_rtcp",
-      "../rtp_rtcp:rtp_rtcp_unittests",
+      "../rtp_rtcp:mock_rtp_rtcp",
       "//testing/gmock",
     ]
 
     # TODO(jschuh): bugs.webrtc.org/1348: fix this warning.
     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" ]
     }
   }
 }