Rename "test" ozone platform to "headless"

chromecast/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.
 
 import("//build/config/features.gni")
 import("//build/config/locales.gni")
 import("//build/config/ui.gni")
 import("//chromecast/build/tests/cast_test.gni")
 import("//chromecast/chromecast.gni")
 import("//tools/grit/repack.gni")
@@ skipping 119 matching lines @@
     ]
   }
 }
 
 # Creates the build and run lists for all test targets.
 cast_test_group_list("cast_test_lists") {
   build_list_path = "$root_out_dir/tests/build_test_list.txt"
 
   run_list_path = "$root_out_dir/tests/run_test_list.txt"
 
-  additional_options = [ "--ozone-platform=test" ]
+  additional_options = [ "--ozone-platform=headless" ]
 
   build_tests = true
 
   test_groups = [ ":cast_tests" ]
 
   if (chromecast_branding != "public") {
     test_groups += [ "//chromecast/internal:internal_cast_tests" ]
   }
 }
 
@@ skipping 123 matching lines @@
          chromecast_branding == "google")
   args = [
            "-b",
            "$chromecast_branding",
            "-g",
            rebase_path("$root_gen_dir/chromecast_strings"),
            "-x",
            rebase_path("$root_out_dir/chromecast_locales"),
          ] + locales
 }