Updated json_to_html to be sync.

tools/html_json_doc/lib/json_to_html.dart

Index: tools/html_json_doc/lib/json_to_html.dart
diff --git a/tools/html_json_doc/lib/json_to_html.dart b/tools/html_json_doc/lib/json_to_html.dart
index d25aa4d0b7e654254ef8e7cafbaa575ef98746be..e6ac183c320b80dbd5a620347873d1e74f68ee3b 100644
--- a/tools/html_json_doc/lib/json_to_html.dart
+++ b/tools/html_json_doc/lib/json_to_html.dart
@@ -66,7 +66,12 @@ Future<bool> convert(Path htmlPath, Path jsonPath) {
   // Find html files. (lister)
   final lister = htmlDir.list(recursive: false);
 
+  var pathList = <String>[];
   lister.onFile = (String path) {
+    pathList.add(path);
+  };
+
+  getFile(String path) {
     final name = new Path.fromNative(path).filename;
 
     // Ignore private classes.
@@ -98,6 +103,9 @@ Future<bool> convert(Path htmlPath, Path jsonPath) {
   };
 
   lister.onDone = (_) {
+    while(!pathList.isEmpty) {
+      getFile(pathList.removeLast());
+    }
 
     fileJson.forEach((key, _) {
       print('WARNING: the following filename was found in the JSON but not in '
@@ -139,13 +147,6 @@ void _convertFile(File file, Map<String, List<String>> comments) {
         '${new Path(file.fullPathSync()).filename}:\n"$key"');
     _anyErrors = true;
   });
-  
-  // TODO(amouravski): file.writeAsStringSync('${Strings.join(fileLines, '\n')}\n');
-  var outputStream = file.openOutputStream();
-  outputStream.writeString(Strings.join(fileLines, '\n'));
-  outputStream.writeString('\n');
-
-  outputStream.onNoPendingWrites = () {
-    outputStream.close();
-  };
+
+ file.writeAsStringSync('${Strings.join(fileLines, '\n')}\n');
 }