diff --git a/test/BUILD.gn b/test/BUILD.gn
index 00b78d43e7..96321ee2d9 100644
--- a/test/BUILD.gn
+++ b/test/BUILD.gn
@@ -255,6 +255,7 @@ if (rtc_include_tests) {
       ":field_trial",
       ":fileutils_override_api",
       ":perf_test",
+      ":resources_dir_flag",
       ":test_support",
       "../rtc_base",
       "../rtc_base:checks",
@@ -500,6 +501,18 @@ rtc_source_set("fileutils") {
   }
 }
 
+rtc_source_set("resources_dir_flag") {
+  testonly = true
+  visibility = [ "*" ]
+  sources = [
+    "testsupport/resources_dir_flag.cc",
+    "testsupport/resources_dir_flag.h",
+  ]
+  deps = [
+    "//third_party/abseil-cpp/absl/flags:flag",
+  ]
+}
+
 # We separate header into own target to make it possible for downstream
 # projects to override implementation.
 rtc_source_set("fileutils_override_api") {
diff --git a/test/test_main_lib.cc b/test/test_main_lib.cc
index 1650d2ac79..178eda7c75 100644
--- a/test/test_main_lib.cc
+++ b/test/test_main_lib.cc
@@ -30,6 +30,7 @@
 #include "test/testsupport/file_utils.h"
 #include "test/testsupport/file_utils_override.h"
 #include "test/testsupport/perf_test.h"
+#include "test/testsupport/resources_dir_flag.h"
 
 #if defined(WEBRTC_WIN)
 #include "rtc_base/win32_socket_init.h"
@@ -81,14 +82,6 @@ ABSL_FLAG(std::vector<std::string>,
 
 #endif
 
-ABSL_FLAG(std::string,
-          resources_dir,
-          "",
-          "Where to look for the runtime dependencies. If not specified, we "
-          "will use a reasonable default depending on where we are running. "
-          "This flag is useful if we copy over test resources to a phone and "
-          "need to tell the tests where their resources are.");
-
 ABSL_FLAG(bool, logs, true, "print logs to stderr");
 ABSL_FLAG(bool, verbose, false, "verbose logs to stderr");
 
diff --git a/test/testsupport/resources_dir_flag.cc b/test/testsupport/resources_dir_flag.cc
new file mode 100644
index 0000000000..a6ab3b537b
--- /dev/null
+++ b/test/testsupport/resources_dir_flag.cc
@@ -0,0 +1,19 @@
+/*
+ *  Copyright (c) 2019 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.
+ */
+
+#include "test/testsupport/resources_dir_flag.h"
+
+ABSL_FLAG(std::string,
+          resources_dir,
+          "",
+          "Where to look for the runtime dependencies. If not specified, we "
+          "will use a reasonable default depending on where we are running. "
+          "This flag is useful if we copy over test resources to a phone and "
+          "need to tell the tests where their resources are.");
diff --git a/test/testsupport/resources_dir_flag.h b/test/testsupport/resources_dir_flag.h
new file mode 100644
index 0000000000..055cc82546
--- /dev/null
+++ b/test/testsupport/resources_dir_flag.h
@@ -0,0 +1,20 @@
+/*
+ *  Copyright (c) 2019 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.
+ */
+
+#include <string>
+
+#ifndef TEST_TESTSUPPORT_RESOURCES_DIR_FLAG_H__
+#define TEST_TESTSUPPORT_RESOURCES_DIR_FLAG_H__
+
+#include "absl/flags/flag.h"
+
+ABSL_DECLARE_FLAG(std::string, resources_dir);
+
+#endif  // TEST_TESTSUPPORT_RESOURCES_DIR_FLAG_H__