Land prep work to enable NaCl in the Linux x64 GN builds.

third_party/harfbuzz-ng/BUILD.gn

 # Copyright 2014 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")
 
 # The GYP build supports system harfbuzz for non-official builds when using
 # pangoft2 1.31.0 or greater (which pulls it in).
 # TODO(brettw) we can consider doing this as well, although the benefit is
 # unclear and requires shelling out to a script to check the version.
 #
 # ChromeOS uses an up-to-date system one that we have control over, so we
 # don't want to bloat the binary more by including another copy.
 
 declare_args() {
-  if (is_linux && (!is_official_build || is_chromeos)) {
+  use_system_harfbuzz = false
+

[Dirk Pranke, 2015/02/05 00:00:14]

We need this change to keep GN from complaining that the arg might be defined in
multiple different places w/ multiple different default values.

This edit should produce no actual changes in the logic, I just rewrote it to
(hopefully) be a little clearer.

+  if (is_linux && (!is_official_build || cpu_arch == "arm" || is_chromeos)) {
     # Since version 1.31.0, pangoft2 which we depend on pulls in harfbuzz
     # anyways. However, we want to have control of the version of harfbuzz
     # we use, so don't use system harfbuzz for official builds, unless we
     # are building for chrome os, where we have the system harfbuzz under
-    # control as well.
+    # control as well. We also never want to use the system harfbuzz when
+    # cross-compiling for ARM.
     use_system_harfbuzz = exec_script(pkg_config_script,
                                       pkg_config_args + [
                                             "--atleast-version=1.31.0",
                                             "pangoft2",
                                           ],
                                       "value")
-  } else {
-    use_system_harfbuzz = false
-  }
-  if (is_linux && cpu_arch == "arm" && !is_chromeos) {
-    # Override use_system_harfbuzz for ARM cross compiling so system
-    # harfbuzz is not used because the corresponding package is not
-    # available.
-    use_system_harfbuzz = false
   }
 }
 
 if (use_system_harfbuzz) {
   import("//build/config/linux/pkg_config.gni")
   pkg_config("harfbuzz_pkgconfig") {
     packages = [ "harfbuzz" ]
   }
   group("harfbuzz-ng") {
     public_configs = [ ":harfbuzz_pkgconfig" ]
@@ skipping 122 matching lines @@
     }
     if (is_mac) {
       sources += [
         "src/hb-coretext.cc",
         "src/hb-coretext.h",
       ]
       defines += [ "HAVE_CORETEXT" ]
     }
   }
 }