GN: Tighten up test target visibility + refactorings

webrtc/tools/network_tester/BUILD.gn

 # Copyright (c) 2017 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 50 matching lines @@
     bundle_data("network_tester_unittests_bundle_data") {
       testonly = true
       sources = network_tester_unittests_resources
       outputs = [
         "{{bundle_resources_dir}}/{{source_file_part}}",
       ]
     }
   }
 
   rtc_source_set("network_tester_unittests") {
+    testonly = true
+
+    # Skip restricting visibility on mobile platforms since the tests on those
+    # gets additional generated targets which would require many lines here to
+    # cover (which would be confusing to read and hard to maintain).
+    if (!is_android && !is_ios) {
+      visibility = [ "//webrtc/tools:tools_unittests" ]
+    }
     sources = [
       "network_tester_unittest.cc",
     ]
 
-    testonly = true
     deps = [
       ":network_tester",
       "//testing/gtest",
       "//webrtc/base:rtc_base_tests_utils",
       "//webrtc/test:test_support",
     ]
 
     if (is_ios) {
       deps += [ ":network_tester_unittests_bundle_data" ]
     }
@@ skipping 73 matching lines @@
       ":network_tester",
       "../../system_wrappers:field_trial_default",
     ]
 
     suppressed_configs += [ "//build/config/android:hide_all_but_jni_onload" ]
     configs += [ "//build/config/android:hide_all_but_jni" ]
 
     output_extension = "so"
   }
 }