Remove use_gconf build flag

All usages of gconf have now been removed, so we can remove the build
flag too. After this, I will remove gconf from the instrumented
libraries, sysroots, and install-build-deps.sh.

Bug: 768027
Change-Id: Idf5e8d60da387b3287f875092feba488217ca642
Reviewed-on: https://chromium-review.googlesource.com/826046Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Commit-Queue: Tim Brown <timbrown@chromium.org>
Cr-Commit-Position: refs/heads/master@{#524120}

build/args/headless.gn

@@ -35,7 +35,6 @@ enable_remoting = false
 use_alsa = false
 use_cups = false
 use_dbus = false
-use_gconf = false
 use_gio = false
 use_kerberos = false
 use_libpci = false

build/config/features.gni

@@ -50,11 +50,6 @@ declare_args() {
 
   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 &&
-              current_toolchain == default_toolchain
-
   use_gio = is_linux && !is_chromeos && !is_chromecast
 }
 #

build/config/linux/atk/BUILD.gn

@@ -7,12 +7,10 @@ import("//build/config/linux/gtk/gtk.gni")
 import("//build/config/linux/pkg_config.gni")
 import("//build/config/ui.gni")
 
-# CrOS doesn't install GTK, gconf or any gnome packages.
+# CrOS doesn't install GTK or any gnome packages.
 assert(!is_chromeos)
 
 # These packages should _only_ be expected when building for a target.
-# If these extra checks are not run, gconf is required when building host
-# tools for a CrOS build.
 assert(current_toolchain == default_toolchain)
 
 if (use_atk) {

build/config/linux/gconf/BUILD.gn

-# Copyright 2016 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/linux/pkg_config.gni")
-
-# CrOS doesn't install GTK, gconf or any gnome packages.
-assert(!is_chromeos && use_gconf)
-
-# These packages should _only_ be expected when building for a target.
-# If these extra checks are not run, gconf is required when building host
-# tools for a CrOS build.
-assert(current_toolchain == default_toolchain)
-
-pkg_config("gconf") {
-  packages = [ "gconf-2.0" ]
-  defines = [ "USE_GCONF" ]
-}