Add observatory_pub_packages snapshot to third_party

observatory_pub_packages/csslib/src/token.dart

Index: observatory_pub_packages/csslib/src/token.dart
===================================================================
--- observatory_pub_packages/csslib/src/token.dart	(revision 0)
+++ observatory_pub_packages/csslib/src/token.dart	(working copy)
@@ -0,0 +1,66 @@
+// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+part of csslib.parser;
+
+/**
+ * A single token in the Dart language.
+ */
+class Token {
+  /** A member of [TokenKind] specifying what kind of token this is. */
+  final int kind;
+
+  /** The location where this token was parsed from. */
+  final SourceSpan span;
+
+  /** The start offset of this token. */
+  int get start => span.start.offset;
+
+  /** The end offset of this token. */
+  int get end => span.end.offset;
+
+  /** Returns the source text corresponding to this [Token]. */
+  String get text => span.text;
+
+  Token(this.kind, this.span);
+
+  /** Returns a pretty representation of this token for error messages. **/
+  String toString() {
+    var kindText = TokenKind.kindToString(kind);
+    var actualText = text.trim();
+    if (kindText != actualText) {
+      if (actualText.length > 10) {
+        actualText = '${actualText.substring(0, 8)}...';
+      }
+      return '$kindText($actualText)';
+    } else {
+      return kindText;
+    }
+  }
+}
+
+/** A token containing a parsed literal value. */
+class LiteralToken extends Token {
+  var value;
+  LiteralToken(int kind, SourceSpan span, this.value) : super(kind, span);
+}
+
+/** A token containing error information. */
+class ErrorToken extends Token {
+  String message;
+  ErrorToken(int kind, SourceSpan span, this.message) : super(kind, span);
+}
+
+/**
+ * CSS ident-token.
+ *
+ * See <http://dev.w3.org/csswg/css-syntax/#typedef-ident-token> and
+ * <http://dev.w3.org/csswg/css-syntax/#ident-token-diagram>.
+ */
+class IdentifierToken extends Token {
+  final String text;
+
+  IdentifierToken(this.text, int kind, SourceSpan span)
+      : super(kind, span);
+}