Update charted to 0.4.8 and roll

packages/petitparser/lib/src/debug/continuation.dart

-part of petitparser.debug;
-
-/// Handler function for the [ContinuationParser].
-typedef Result ContinuationHandler(
-    Result continuation(Context context), Context context);
-
-/// Continuation parser that when activated captures a continuation function
-/// and passes it together with the current context into the handler.
-///
-/// Handlers are not required to call the continuation, but can completely ignore
-/// it, call it multiple times, and/or store it away for later use. Similarly
-/// handlers can modify the current context and/or modify the returned result.
-///
-/// The following example shows a simple wrapper. Messages are printed before and
-/// after the `digit()` parser is activated:
-///
-///     var wrapped = digit();
-///     var parser = new ContinuationParser(wrapped, (continuation, context) {
-///       print('Parser will be activated, the context is $context.');
-///       var result = continuation(context);
-///       print('Parser was activated, the result is $result.');
-///       return result;
-///     });
-///
-/// See [profile], [progress], and [trace] for more elaborate examples.
-class ContinuationParser extends DelegateParser {
-  final ContinuationHandler handler;
-
-  ContinuationParser(parser, this.handler) : super(parser);
-
-  @override
-  Result parseOn(Context context) {
-    return handler((result) => super.parseOn(result), context);
-  }
-
-  @override
-  Parser copy() => new ContinuationParser(children[0], handler);
-}