diff --git a/ci/check_gn_format.py b/ci/check_gn_format.py
index 5cc889c808aa8..d7611a4f91415 100755
--- a/ci/check_gn_format.py
+++ b/ci/check_gn_format.py
@@ -25,7 +25,7 @@ def main():
   parser = argparse.ArgumentParser();
 
   parser.add_argument('--gn-binary', dest='gn_binary', required=True, type=str)
-  parser.add_argument('--dry-run', dest='dry_run', default=True, type=str)
+  parser.add_argument('--dry-run', dest='dry_run', default=False, action='store_true')
   parser.add_argument('--root-directory', dest='root_directory', required=True, type=str)
 
   args = parser.parse_args()
@@ -35,16 +35,15 @@ def main():
 
   gn_command = [ gn_binary, 'format']
 
-  if args.dry_run == 'false':
+  if args.dry_run:
     gn_command.append('--dry-run')
 
-
   for gn_file in GetGNFiles(args.root_directory):
     if subprocess.call(gn_command + [ gn_file ]) != 0:
       print "ERROR: '%s' is incorrectly formatted." % os.path.relpath(gn_file, args.root_directory)
       print "Format the same with 'gn format' using the 'gn' binary in //buildtools."
       print "Or, run ./ci/check_gn_format.py with '--dry-run false'"
-      return -1
+      return 1
 
   return 0
 
diff --git a/ci/format.sh b/ci/format.sh
index ceacb5af07938..bff94d77b07dd 100755
--- a/ci/format.sh
+++ b/ci/format.sh
@@ -75,4 +75,4 @@ if [[ ! -z "$TRAILING_SPACES" ]]; then
 fi
 
 # Check GN format consistency
-./ci/check_gn_format.py --dry-run true --root-directory . --gn-binary "third_party/gn/gn"
+./ci/check_gn_format.py --dry-run --root-directory . --gn-binary "third_party/gn/gn"