Roll Observatory packages and add a roll script

packages/html/lib/parser_console.dart

 /// This library adds `dart:io` support to the HTML5 parser. Call
 /// [initDartIOSupport] before calling the [parse] methods and they will accept
 /// a [RandomAccessFile] as input, in addition to the other input types.
 library parser_console;
 
 import 'dart:io';
 import 'parser.dart';
 import 'src/inputstream.dart' as inputstream;
 
 /// Adds support to the [HtmlParser] for running on a console VM. In particular
@@ skipping 22 matching lines @@
     if (read <= 0) {
       // This could happen if, for example, the file was resized while
       // we're reading. Just shrink the bytes array and move on.
       bytes = bytes.sublist(0, bytesRead);
       break;
     }
     bytesRead += read;
   }
   return bytes;
 }