headless: Replace is_headless gn setting with an args template

build/config/features.gni

Index: build/config/features.gni
diff --git a/build/config/features.gni b/build/config/features.gni
index d17e34cb6f0746f9666f2184c299f3b4c4f4b183..72a5b5e576a95ed86d134ca627f72d14c215ad0e 100644
--- a/build/config/features.gni
+++ b/build/config/features.gni
@@ -16,7 +16,6 @@
 
 import("//build/config/chrome_build.gni")
 import("//build/config/chromecast_build.gni")
-import("//build/config/headless_build.gni")
 if (is_android) {
   import("//build/config/android/config.gni")
 }
@@ -64,7 +63,7 @@ declare_args() {
 
   enable_autofill_dialog = !is_ios
 
-  enable_remoting = !is_ios && !is_chromecast && !is_headless
+  enable_remoting = !is_ios && !is_chromecast
 
   # Enable hole punching for the protected video.
   enable_video_hole = is_android
@@ -94,11 +93,29 @@ declare_args() {
   # Note: this setting is ignored if is_chrome_branded.
   fieldtrial_testing_like_official_build = is_chrome_branded
 
-  use_cups = (is_desktop_linux || is_mac) && !is_chromecast && !is_headless
+  use_cups = (is_desktop_linux || is_mac) && !is_chromecast
 
   # Enables Wi-Fi Display functionality
   # WARNING: This enables MPEG Transport Stream (MPEG-TS) encoding!
   enable_wifi_display = false
+
+  # libudev usage. This currently only affects the content layer.
+  use_udev = is_linux && !is_chromecast
+
+  use_dbus = is_linux && !is_chromecast
+
+  # Option controlling the use of GConf (the classic GNOME configuration
+  # system).
+  use_gconf = is_linux && !is_chromeos && !is_chromecast
+
+  use_gio = is_linux && !is_chromeos && !is_chromecast
+
+  # Enable basic printing support and UI.
+  enable_basic_printing = !is_chromeos && !is_chromecast && !is_ios
+
+  # Enable printing with print preview. It does not imply
+  # enable_basic_printing. It's possible to build Chrome with preview only.
+  enable_print_preview = !is_android && !is_chromecast && !is_ios
 }
 
 # Additional dependent variables -----------------------------------------------
@@ -108,23 +125,12 @@ declare_args() {
 #   2: Use only CLD2.
 cld_version = 2
 
-# libudev usage. This currently only affects the content layer.
-use_udev = is_linux && !is_chromecast && !is_headless
-
 # Enable the spell checker.
 enable_spellcheck = !is_ios
 
 # Use the operating system's spellchecker rather than hunspell.
 use_browser_spellchecker = is_android || is_mac
 
-# Enable basic printing support and UI.
-enable_basic_printing =
-    !is_chromeos && !is_chromecast && !is_ios && !is_headless
-
-# Enable printing with print preview. It does not imply
-# enable_basic_printing. It's possible to build Chrome with preview only.
-enable_print_preview = !is_android && !is_chromecast && !is_ios && !is_headless
-
 # Enables the use of CDMs in pepper plugins.
 enable_pepper_cdms =
     enable_plugins && (is_linux || is_mac || is_win) && !is_chromecast
@@ -143,8 +149,6 @@ enable_notifications = !is_ios
 
 enable_web_speech = !is_android && !is_ios
 
-use_dbus = is_linux && !is_chromecast && !is_headless
-
 enable_task_manager = !is_ios && !is_android
 
 enable_themes = !is_android && !is_ios
@@ -168,14 +172,8 @@ enable_chromevox_next = false
 # Use brlapi from brltty for braille display support.
 use_brlapi = is_chromeos
 
-# Option controlling the use of GConf (the classic GNOME configuration
-# system).
-use_gconf = is_linux && !is_chromeos && !is_chromecast && !is_headless
-
 # Enable WebVR support by default on Android
 # Still requires command line flag to access API
 enable_webvr = is_android
 
-use_gio = is_linux && !is_chromeos && !is_chromecast && !is_headless
-
 enable_configuration_policy = !is_ios