Remove the gn target //build/linux:fontconfig in favor of //third_party/fontconfig.

Review-Url: https://codereview.chromium.org/2923973004
Cr-Commit-Position: refs/heads/master@{#478106}
diff --git a/chrome/browser/extensions/BUILD.gn b/chrome/browser/extensions/BUILD.gn
index 1186a9b..1764a87 100644
--- a/chrome/browser/extensions/BUILD.gn
+++ b/chrome/browser/extensions/BUILD.gn
@@ -1032,7 +1032,7 @@
   }
 
   if (is_linux) {
-    deps += [ "//build/linux:fontconfig" ]
+    deps += [ "//third_party/fontconfig" ]
 
     if (use_dbus) {
       deps += [ "//dbus" ]