Use Flow to typecheck JavaScript code.

Change-Id: I9c0c9b5aa74d592a04eb6533e64669f1896fb7cd
diff --git a/src/main/resources/META-INF/resources/yarn.lock b/src/main/resources/META-INF/resources/yarn.lock
index 2b69a44..1a2a5a1 100644
--- a/src/main/resources/META-INF/resources/yarn.lock
+++ b/src/main/resources/META-INF/resources/yarn.lock
@@ -1051,6 +1051,11 @@
   resolved "https://registry.yarnpkg.com/find-package-json/-/find-package-json-1.2.0.tgz#4057d1b943f82d8445fe52dc9cf456f6b8b58083"
   integrity sha512-+SOGcLGYDJHtyqHd87ysBhmaeQ95oWspDKnMXBrnQ9Eq4OkLNqejgoaD8xVWu6GPa0B6roa6KinCMEMcVeqONw==
 
+flow-bin@^0.118.0:
+  version "0.118.0"
+  resolved "https://registry.yarnpkg.com/flow-bin/-/flow-bin-0.118.0.tgz#fb706364a58c682d67a2ca7df39396467dc397d1"
+  integrity sha512-jlbUu0XkbpXeXhan5xyTqVK1jmEKNxE8hpzznI3TThHTr76GiFwK0iRzhDo4KNy+S9h/KxHaqVhTP86vA6wHCg==
+
 fs.realpath@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/fs.realpath/-/fs.realpath-1.0.0.tgz#1504ad2523158caa40db4a2787cb01411994ea4f"