Add browser_extensions to GN build.

build/config/linux/BUILD.gn

 # Copyright (c) 2013 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/linux/pkg_config.gni")
+import("//build/config/features.gni")
 import("//build/config/sysroot.gni")
 import("//build/config/ui.gni")
 import("//tools/generate_library_loader/generate_library_loader.gni")
 
 config("sdk") {
   if (sysroot != "") {
     cflags = [ "--sysroot=" + sysroot ]
     ldflags = [ "--sysroot=" + sysroot ]
 
     # Need to get some linker flags out of the sysroot.
@@ skipping 93 matching lines @@
 
 config("libresolv") {
   libs = [ "resolv" ]
 }
 
 pkg_config("gconf") {
   packages = [ "gconf-2.0" ]
   defines = [ "USE_GCONF" ]
 }
 
+# If brlapi isn't needed, don't require it to be installed.
+if (use_brlapi) {
+  config("brlapi_config") {
+    defines = [ "USE_BRLAPI" ]
+  }
+
+  # TODO(GYP) linux_link_brlapi support. Is this needed?
+  generate_library_loader("libbrlapi") {
+    name = "LibBrlapiLoader"
+    output_h = "libbrlapi.h"
+    output_cc = "libbrlapi_loader.cc"
+    header = "<brlapi.h>"
+    config = ":brlapi_config"
+  }
+}
+
 pkg_config("gio_config") {
   packages = [ "gio-2.0" ]
   defines = [ "USE_GIO" ]
   ignore_libs = true  # Loader generated below.
 }
 
 # This generates a target named "gio".
 generate_library_loader("gio") {
   name = "LibGioLoader"
   output_h = "libgio.h"
@@ skipping 23 matching lines @@
     "pci_alloc",
     "pci_init",
     "pci_cleanup",
     "pci_scan_bus",
     "pci_fill_info",
     "pci_lookup_name",
   ]
 }
 
 # Looking for libspeechd? Use //third_party/speech-dispatcher