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

third_party/harfbuzz-ng/BUILD.gn

Index: third_party/harfbuzz-ng/BUILD.gn
diff --git a/third_party/harfbuzz-ng/BUILD.gn b/third_party/harfbuzz-ng/BUILD.gn
index 000a9cc361e338973203417895bb6dd993ed4164..20908cf807faa6e1d718ce9e20e5676e21c2edb3 100644
--- a/third_party/harfbuzz-ng/BUILD.gn
+++ b/third_party/harfbuzz-ng/BUILD.gn
@@ -13,26 +13,21 @@ import("//build/config/linux/pkg_config.gni")
 # 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
   }
 }