[GN] Guard the "pangocairo" config with (use_pango || use_cairo).

build/config/linux/BUILD.gn

Index: build/config/linux/BUILD.gn
diff --git a/build/config/linux/BUILD.gn b/build/config/linux/BUILD.gn
index 1b3d9f9c867de3f07eff9744cbacf66dfa43af47..26ae44c94e3bc5bd12d823c8fbafd9731b89b67f 100644
--- a/build/config/linux/BUILD.gn
+++ b/build/config/linux/BUILD.gn
@@ -46,12 +46,16 @@ pkg_config("glib") {
   ]
 }
 
-pkg_config("pangocairo") {
-  packages = [ "pangocairo" ]
+if (use_pango || use_cairo) {
+  pkg_config("pangocairo") {
+    packages = [ "pangocairo" ]
+  }
 }
 
-pkg_config("pangoft2") {
-  packages = [ "pangoft2" ]
+if (use_pango) {
+  pkg_config("pangoft2") {
+    packages = [ "pangoft2" ]
+  }
 }
 
 # Note: if your target also depends on //dbus, you don't need to add this