Adds mustash_unittests to gn bots

BUG=none
TEST=none
[email protected]

Review URL: https://codereview.chromium.org/1420713004

Cr-Commit-Position: refs/heads/master@{#357413}
diff --git a/BUILD.gn b/BUILD.gn
index 623f1250..bfa2537 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -550,6 +550,10 @@
     deps += [ "//components/proximity_auth:proximity_auth_unittests" ]
   }
 
+  if (!is_component_build && (is_win || is_linux)) {
+    deps += [ "//components/mus/example:all" ]
+  }
+
   if (is_linux && !is_chromeos) {
     # TODO(GYP): Figure out if any of these should be in gn_all
     # and figure out how cross-platform they are