GN: Refactor modules_unittests to eliminate package boundary violations.

webrtc/modules/bitrate_controller/BUILD.gn

Index: webrtc/modules/bitrate_controller/BUILD.gn
diff --git a/webrtc/modules/bitrate_controller/BUILD.gn b/webrtc/modules/bitrate_controller/BUILD.gn
index 1bc8cc4c92672bf316b97a043595669650fcdc48..b2747db26c3645f51671f43f6aee0d1db430f534 100644
--- a/webrtc/modules/bitrate_controller/BUILD.gn
+++ b/webrtc/modules/bitrate_controller/BUILD.gn
@@ -42,3 +42,24 @@ rtc_static_library("bitrate_controller") {
     "../rtp_rtcp",
   ]
 }
+
+if (rtc_include_tests) {
+  rtc_source_set("bitrate_controller_unittests") {
+    testonly = true
+    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" ]
+    }
+  }
+}