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..87770c7ffae8f9504cfa9494dbc1f0f8c4481519 100644
--- a/ui/ozone/ozone.gni
+++ b/ui/ozone/ozone.gni
@@ -27,6 +27,7 @@ declare_args() {
   ozone_platform_gbm = false
   ozone_platform_ozonex = false
   ozone_platform_test = false
+  ozone_platform_headless = false
 
   if (ozone_auto_platforms) {
     if (is_chromecast) {
@@ -41,6 +42,9 @@ declare_args() {
         ozone_platform_egltest = true
         ozone_platform_ozonex = true
       }
+    } else if (is_headless) {
+      ozone_platform = "headless"

[Sami, 2015/10/26 16:47:07]

This means we won't have to override the platform manually at runtime anymore,
right?

[altimin, 2015/10/26 17:24:21]

Yes!

+      ozone_platform_headless = true
     } else {
       # Use test as the default platform.
       ozone_platform = "test"