headless: Add gn setting headless mode

The is_headless setting configures the build in the same
way as the embedded flag in gyp.

Contributions by Alexander Timin <altimin@chromium.org> and
Alex Clarke <alexclarke@chromium.org>.

BUG=546953,318413

Review URL: https://codereview.chromium.org/1410883007

Cr-Commit-Position: refs/heads/master@{#359096}

4 files changed, 23 insertions, 10 deletions

diff --git a/build/config/features.gni b/build/config/features.gni
index e06daca..669ad5d 100644
--- a/build/config/features.gni
+++ b/build/config/features.gni
@@ -16,6 +16,7 @@
 
 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")
 }
@@ -86,7 +87,7 @@ declare_args() {
 
   enable_one_click_signin = is_win || is_mac || (is_linux && !is_chromeos)
 
-  enable_remoting = !is_ios && !is_android && !is_chromecast
+  enable_remoting = !is_ios && !is_android && !is_chromecast && !is_headless
 
   # Enable hole punching for the protected video.
   enable_video_hole = is_android
@@ -116,7 +117,7 @@ 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
+  use_cups = (is_desktop_linux || is_mac) && !is_chromecast && !is_headless
 }
 
 # Additional dependent variables -----------------------------------------------
@@ -127,7 +128,7 @@ declare_args() {
 cld_version = 2
 
 # libudev usage. This currently only affects the content layer.
-use_udev = is_linux && !is_chromecast
+use_udev = is_linux && !is_chromecast && !is_headless
 
 # Enable the spell checker.
 enable_spellcheck = !is_ios
@@ -136,11 +137,12 @@ enable_spellcheck = !is_ios
 use_browser_spellchecker = is_android || is_mac
 
 # Enable basic printing support and UI.
-enable_basic_printing = !is_chromeos && !is_chromecast && !is_ios
+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
+enable_print_preview = !is_android && !is_chromecast && !is_ios && !is_headless
 
 # Enables the use of CDMs in pepper plugins.
 enable_pepper_cdms =
@@ -159,7 +161,7 @@ enable_notifications = !is_ios
 
 enable_web_speech = !is_android && !is_ios
 
-use_dbus = is_linux && !is_chromecast
+use_dbus = is_linux && !is_chromecast && !is_headless
 
 enable_extensions = !is_android && !is_ios
 
@@ -191,7 +193,7 @@ use_brlapi = is_chromeos
 
 # Option controlling the use of GConf (the classic GNOME configuration
 # system).
-use_gconf = is_linux && !is_chromeos && !is_chromecast
+use_gconf = is_linux && !is_chromeos && !is_chromecast && !is_headless
 
 # Whether to back up data before sync.
 enable_pre_sync_backup = is_win || is_mac || (is_linux && !is_chromeos)
@@ -199,3 +201,5 @@ enable_pre_sync_backup = is_win || is_mac || (is_linux && !is_chromeos)
 # Enable WebVR support by default on Android
 # Still requires command line flag to access API
 enable_webvr = is_android
+
+use_gio = is_desktop_linux && !is_headless
diff --git a/build/config/headless_build.gni b/build/config/headless_build.gni
new file mode 100644
index 0000000..1788b25
--- /dev/null
+++ b/build/config/headless_build.gni
@@ -0,0 +1,8 @@
+# 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.
+
+declare_args() {
+  # Configure the build for headless mode. See crbug.com/546953.
+  is_headless = false
+}
diff --git a/build/config/ui.gni b/build/config/ui.gni
index e534366..3acf655 100644
--- a/build/config/ui.gni
+++ b/build/config/ui.gni
@@ -15,16 +15,17 @@
 # to set up feature flags.
 
 import("//build/config/chromecast_build.gni")
+import("//build/config/headless_build.gni")
 
 declare_args() {
   # Indicates if Ash is enabled. Ash is the Aura Shell which provides a
   # desktop-like environment for Aura. Requires use_aura = true
-  use_ash = (is_win || is_linux) && !is_chromecast
+  use_ash = (is_win || is_linux) && !is_chromecast && !is_headless
 
   # Indicates if Ozone is enabled. Ozone is a low-level library layer for Linux
   # that does not require X11. Enabling this feature disables use of glib, x11,
   # Pango, and Cairo. Default to false on non-Chromecast builds.
-  use_ozone = is_chromecast && !is_android
+  use_ozone = (is_chromecast || is_headless) && !is_android
 
   # Indicates if Aura is enabled. Aura is a low-level windowing library, sort
   # of a replacement for GDI or GTK.
diff --git a/build/linux/BUILD.gn b/build/linux/BUILD.gn
index 754859a..a66d86c 100644
--- a/build/linux/BUILD.gn
+++ b/build/linux/BUILD.gn
@@ -30,7 +30,7 @@ if (use_brlapi) {
     functions = gypi_values.libbrlapi_functions
   }
 }
-if (is_desktop_linux) {
+if (use_gio) {
   pkg_config("gio_config") {
     packages = [ "gio-2.0" ]