Suppress env var error output

lib/util.js

@@ -393,6 +393,18 @@ const util = {
   // TODO(bridiver) - this should move to gn and windows should call signApp like other platforms
   signWinBinaries: () => {
     // Copy & sign only binaries for widevine sig file generation.
+    if (config.buildConfig !== 'Release' || config.skip_signing) {
+      console.log('binary signing is skipped because this is not official build or --skip_signing is used')
+      return
+    }
+
+    if (process.env.CERT === undefined || process.env.SIGNTOOL_ARGS === undefined) {
+      //console.log('binary signing is skipped because of missing env vars')
+      //return
+    }
+
+     console.log('signing win binaries...')
+
     // With this, create_dist doesn't trigger rebuild because original binaries is not modified.
     const dir = path.join(config.outputDir, 'signed_binaries')
     if (!fs.existsSync(dir))