[libfuzzer] support of custom libfuzzer options via .options file.

testing/libfuzzer/tests/BUILD.gn

 # Copyright 2015 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.
 #
 # Fuzzing Infrastructure Tests
 
 import("//testing/test.gni")
 import("//testing/libfuzzer/fuzzer_test.gni")
 
 test("libfuzzer_tests") {
   sources = [
     "fuzzer_launcher_test.cc",
   ]
   deps = [
+    ":test_dict_and_params_launcher.sh",
     ":test_dict_launcher.sh",
+    ":test_params_launcher.sh",
     "//base",
     "//testing/gmock",
     "//testing/gtest",
     "//testing/gtest:gtest_main",
   ]
   data_deps = [
     ":print_args",
   ]
 }
 
 fuzzer_test_launcher("test_dict_launcher.sh") {
   fuzzer_name = "print_args.py"
   dict = "test_dict"
 }
 
+fuzzer_test_launcher("test_params_launcher.sh") {
+  fuzzer_name = "print_args.py"
+  params = "-test_param=test_value"
+}
+
+fuzzer_test_launcher("test_dict_and_params_launcher.sh") {
+  fuzzer_name = "print_args.py"
+  dict = "test_dict"
+  params = "-test_param=test_value"
+}
+
 copy("print_args") {
   sources = [
     "print_args.py",
   ]
   outputs = [
     "$root_build_dir/print_args.py",
   ]
 }