Add two missing tests to gn build

chrome/test/BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/chrome_build.gni")
 import("//build/config/compiler/compiler.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//chrome/chrome_tests.gni")
@@ skipping 1295 matching lines @@
         "../browser/printing/cloud_print/test/cloud_print_proxy_process_browsertest.cc",
         "../browser/printing/print_preview_dialog_controller_browsertest.cc",
         "../browser/printing/print_preview_pdf_generated_browsertest.cc",
         "../browser/service_process/service_process_control_browsertest.cc",
         "../browser/ui/webui/print_preview/print_preview_ui_browsertest.cc",
         "data/webui/print_preview.cc",
         "data/webui/print_preview.h",
       ]
     }
     if (enable_mdns) {
-      sources += [ "../browser/ui/webui/local_discovery/local_discovery_ui_browsertest.cc" ]
+      sources += [
+        "../browser/extensions/api/gcd_private/gcd_private_apitest.cc",
+        "../browser/ui/webui/local_discovery/local_discovery_ui_browsertest.cc",
+      ]
     }
     if (use_brlapi) {
       deps += [ "//build/linux:libbrlapi" ]
     } else {
       sources -= [ "../browser/extensions/api/braille_display_private/braille_display_private_apitest.cc" ]
     }
     if (is_chrome_branded) {
       sources -= [
         # These tests depend on single process mode, which is disabled in
         # official builds.
@@ skipping 949 matching lines @@
 if (is_android) {
   android_library("unit_tests_java") {
     java_files = [ "android/unit_tests_apk/src/org/chromium/chrome/unit_tests_apk/ChromeNativeTestApplication.java" ]
     deps = [
       "//base:base_java",
       "//chrome/android:chrome_java",
       "//content/public/android:content_java",
     ]
   }
 }