GN: Tighten up test target visibility + refactorings

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 702d3e7b9c17619d0657fd49ba2788891883d7bc..696d1c096c563fd3148da31cb0970a8de3819a7f 100644
--- a/webrtc/modules/remote_bitrate_estimator/BUILD.gn
+++ b/webrtc/modules/remote_bitrate_estimator/BUILD.gn
@@ -127,6 +127,9 @@ if (rtc_include_tests) {
 
   rtc_source_set("remote_bitrate_estimator_perf_tests") {
     testonly = true
+    if (!is_android && !is_ios) {  # Generated targets makes this check break.
+      visibility = [ "//webrtc:webrtc_perf_tests" ]
+    }
     sources = [
       "remote_bitrate_estimators_test.cc",
     ]
@@ -144,9 +147,11 @@ if (rtc_include_tests) {
 
   rtc_source_set("remote_bitrate_estimator_unittests") {
     testonly = true
+    if (!is_android && !is_ios) {  # Generated targets makes this check break.
+      visibility = [ "//webrtc/modules:modules_unittests" ]
+    }
     sources = [
       "aimd_rate_control_unittest.cc",
-      "include/mock/mock_remote_bitrate_observer.h",
       "inter_arrival_unittest.cc",
       "overuse_detector_unittest.cc",
       "remote_bitrate_estimator_abs_send_time_unittest.cc",
@@ -162,6 +167,7 @@ if (rtc_include_tests) {
     ]
     deps = [
       ":bwe_simulator_lib",
+      ":mock_remote_bitrate_observer",
       ":remote_bitrate_estimator",
       "../..:webrtc_common",
       "../../base:rtc_base",
@@ -185,6 +191,17 @@ if (rtc_include_tests) {
     }
   }
 
+  rtc_source_set("mock_remote_bitrate_observer") {
+    testonly = true
+    sources = [
+      "include/mock/mock_remote_bitrate_observer.h",
+    ]
+    deps = [
+      ":remote_bitrate_estimator",
+      "../../test:test_support",
+    ]
+  }
+
   rtc_test("bwe_simulations_tests") {
     testonly = true