Add observatory_pub_packages snapshot to third_party

observatory_pub_packages/html5lib/parser_console.dart

Index: observatory_pub_packages/html5lib/parser_console.dart
===================================================================
--- observatory_pub_packages/html5lib/parser_console.dart	(revision 0)
+++ observatory_pub_packages/html5lib/parser_console.dart	(working copy)
@@ -0,0 +1,42 @@
+/// 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
+/// this means it will be able to handle `dart:io` and [RandomAccessFile]s as
+/// input to the various [parse] methods.
+void useConsole() {
+  inputstream.consoleSupport = new _ConsoleSupport();
+}
+
+class _ConsoleSupport extends inputstream.ConsoleSupport {
+  List<int> bytesFromFile(source) {
+    if (source is! RandomAccessFile) return null;
+    return readAllBytesFromFile(source);
+  }
+}
+
+// TODO(jmesserly): this should be `RandomAccessFile.readAllBytes`.
+/// Synchronously reads all bytes from the [file].
+List<int> readAllBytesFromFile(RandomAccessFile file) {
+  int length = file.lengthSync();
+  var bytes = new List<int>(length);
+
+  int bytesRead = 0;
+  while (bytesRead < length) {
+    int read = file.readIntoSync(bytes, bytesRead, length - bytesRead);
+    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;
+}