Fix documentation based on dartdoc's warnings (#11428)

diff --git a/dev/tools/java_and_objc_doc.dart b/dev/tools/java_and_objc_doc.dart
index f02f9d7..0998678 100644
--- a/dev/tools/java_and_objc_doc.dart
+++ b/dev/tools/java_and_objc_doc.dart
@@ -13,21 +13,16 @@
 /// This script downloads an archive of Javadoc and objc doc for the engine from
 /// the artifact store and extracts them to the location used for Dartdoc.
 Future<Null> main(List<String> args) async {
-  final String engineVersion =
-      new File('bin/internal/engine.version').readAsStringSync().trim();
+  final String engineVersion = new File('bin/internal/engine.version').readAsStringSync().trim();
 
-  final String javadocUrl =
-      'https://storage.googleapis.com/flutter_infra/flutter/$engineVersion/android-javadoc.zip';
+  final String javadocUrl = 'https://storage.googleapis.com/flutter_infra/flutter/$engineVersion/android-javadoc.zip';
   generateDocs(javadocUrl, 'javadoc', 'io/flutter/view/FlutterView.html');
 
-  final String objcdocUrl =
-      'https://storage.googleapis.com/flutter_infra/flutter/$engineVersion/ios-objcdoc.zip';
-  generateDocs(
-      objcdocUrl, 'objcdoc', 'Classes/FlutterViewController.html');
+  final String objcdocUrl = 'https://storage.googleapis.com/flutter_infra/flutter/$engineVersion/ios-objcdoc.zip';
+  generateDocs(objcdocUrl, 'objcdoc', 'Classes/FlutterViewController.html');
 }
 
-Future<Null> generateDocs(
-    final String url, String docName, String checkFile) async {
+Future<Null> generateDocs(String url, String docName, String checkFile) async {
   final http.Response response = await http.get(url);
 
   final Archive archive = new ZipDecoder().decodeBytes(response.bodyBytes);