Add chrome perf tests and sniffer to GN build.

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 7f5b2e3f5757a0de1ba525d0ac2ef97cc93c414d..d48eb08d572c632a0ee433a0c1090bd12bd088cb 100644
--- a/third_party/harfbuzz-ng/BUILD.gn
+++ b/third_party/harfbuzz-ng/BUILD.gn
@@ -2,6 +2,8 @@
 # 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
@@ -11,7 +13,26 @@
 # don't want to bloat the binary more by including another copy.
 
 declare_args() {
-  use_system_harfbuzz = is_chromeos
+  if (is_chromeos) {
+    # ChromeOS includes an up-to-date system harfbuzz that we have control
+    # over, so it use the system one by default.

[Dirk Pranke, 2014/11/08 01:27:13]

you probably already realize this, but if you build w/ os="chromeos" on Precise,
we get the system harfbuzz, which is too old, and so we have to override this
default on the bots.

I would say this is moot since devs are mostly all on Trusty now, but it's not
clear when the bots will be updated.

Think it's worth changing this logic somehow to account for this, or just force
callers to specify the flag when needed?

+    use_system_harfbuzz = true
+  } else if (is_official_build) {
+    # For official builds, we want to control the Harbuzz version so always
+    # use our included one. Currently the sysroot includes a version of pangoft
+    # that doesn't link to harfbuzz, so there are no linker problems. If we
+    # update that version, we'll need to work around the duplicate symbols some
+    # other way.
+    use_system_harfbuzz = false
+  } else {
+    # Use the system harfbuzz for newer versions of pangoft, and not for older
+    # ones. pangoft links to the system harfbuzz starting with 1.31.0, which
+    # causes duplicate symbols when we link our own version.
+    use_system_harfbuzz = exec_script(
+        pkg_config_script,
+        pkg_config_args + [ "--atleast-version=1.31.0", "pangoft2" ],
+        "value")
+  }
 }
 
 if (use_system_harfbuzz) {
@@ -28,7 +49,7 @@ if (use_system_harfbuzz) {
     include_dirs = [ "src" ]
   }
 
-  source_set("harfbuzz-ng") {
+  static_library("harfbuzz-ng") {
     sources = [
       "src/hb-atomic-private.hh",
       "src/hb-blob.cc",