Fix SysStrings unit test failure on Chromecast

base/BUILD.gn

 # Copyright (c) 2013 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/ui.gni")
 import("//testing/test.gni")
 
 if (is_android) {
   import("//build/config/android/rules.gni")
 }
@@ skipping 1401 matching lines @@
     "win/scoped_bstr_unittest.cc",
     "win/scoped_comptr_unittest.cc",
     "win/scoped_process_information_unittest.cc",
     "win/scoped_variant_unittest.cc",
     "win/shortcut_unittest.cc",
     "win/startup_information_unittest.cc",
     "win/win_util_unittest.cc",
     "win/wrapped_window_proc_unittest.cc",
   ]
 
+  defines = []
+
   deps = [
     ":base",
     ":i18n",
     ":message_loop_tests",
     ":prefs",
     ":prefs_test_support",
     "//base/allocator",
     "//base/test:run_all_unittests",
     "//base/test:test_support",
     "//base/third_party/dynamic_annotations",
     "//base/third_party/nspr",
     "//testing/gmock",
     "//testing/gtest",
     "//third_party/icu",
   ]
 
+  # Allow more direct string conversions on platforms with native utf8
+  # strings
+  if (is_mac || is_ios || is_chromeos) {
+    defines += [ "SYSTEM_NATIVE_UTF8" ]
+  }
+
   if (is_android) {
     apk_deps = [
       ":base_java",
       ":base_java_unittest_support",
     ]
   }
 
   if (is_ios) {
     sources -= [
       "process/memory_unittest.cc",
@@ skipping 14 matching lines @@
       "sys_string_conversions_mac_unittest.mm",
     ]
     set_sources_assignment_filter(sources_assignment_filter)
 
     # TODO(GYP): dep on copy_test_data_ios action.
   }
 
   if (is_linux) {
     sources -= [ "file_version_info_unittest.cc" ]
     sources += [ "nix/xdg_util_unittest.cc" ]
-    defines = [ "USE_SYMBOLIZE" ]
+    defines += [ "USE_SYMBOLIZE" ]
     if (use_glib) {
       configs += [ "//build/config/linux:glib" ]
     }
   }
 
   if (!is_linux || use_ozone) {
     sources -= [ "message_loop/message_pump_glib_unittest.cc" ]
   }
 
   if (is_posix || is_ios) {
@@ skipping 109 matching lines @@
 
   # GYP: //base.gyp:base_java_unittest_support
   android_library("base_java_unittest_support") {
     deps = [
       ":base_java",
     ]
     java_files =
         [ "test/android/java/src/org/chromium/base/ContentUriTestUtils.java" ]
   }
 }