Rename "test" ozone platform to "headless"

ui/ozone/ozone.gni

Index: ui/ozone/ozone.gni
diff --git a/ui/ozone/ozone.gni b/ui/ozone/ozone.gni
index cb6f62ee28c7889697ebb5a4f9d743ea7969b9ad..15e909dedb8c96516d331c1cb7b808e97b54270b 100644
--- a/ui/ozone/ozone.gni
+++ b/ui/ozone/ozone.gni
@@ -26,14 +26,14 @@ declare_args() {
   ozone_platform_egltest = false
   ozone_platform_gbm = false
   ozone_platform_ozonex = false
-  ozone_platform_test = false
+  ozone_platform_headless = false
 
   if (ozone_auto_platforms) {
     if (is_chromecast) {
       # The default platform used at runtime is "cast".
       ozone_platform = "cast"
       ozone_platform_cast = true
-      ozone_platform_test = true
+      ozone_platform_headless = true
 
       # For desktop Chromecast builds, override the default "cast" platform with
       # --ozone_platform=egltest
@@ -42,13 +42,13 @@ declare_args() {
         ozone_platform_ozonex = true
       }
     } else {
-      # Use test as the default platform.
-      ozone_platform = "test"
+      # Use headless as the default platform.
+      ozone_platform = "headless"
 
       # Build all platforms whose deps are in install-build-deps.sh.
       # Only these platforms will be compile tested by buildbots.
       ozone_platform_gbm = true
-      ozone_platform_test = true
+      ozone_platform_headless = true
       ozone_platform_egltest = true
     }
   }