Automatically create resultbaseurl for GCS if it doesn't exist. (#3259)

lib/cli/cli.js

@@ -1573,6 +1573,19 @@ module.exports.parseCommandLine = function parseCommandLine() {
     );
   }
 
+  if (
+    argv.gcs &&
+    argv.gcs.bucketname &&
+    !argv.resultBaseUrl &&
+    !argv.resultBaseURL
+  ) {
+    set(
+      argv,
+      'resultBaseURL',
+      'https://storage.googleapis.com/' + argv.gcs.bucketname
+    );
+  }
+
   let urlsMetaData = cliUtil.getAliases(argv._, argv.urlAlias, argv.groupAlias);
   // Copy the alias so it is also used by Browsertime
   if (argv.urlAlias) {