Make dart:convert strong mode clean.

pkg/analysis_server/benchmark/integration/input_converter.dart

Index: pkg/analysis_server/benchmark/integration/input_converter.dart
diff --git a/pkg/analysis_server/benchmark/integration/input_converter.dart b/pkg/analysis_server/benchmark/integration/input_converter.dart
index d743d6cc1fd09748b045b1709ce1d97aedae79d5..14ffd96e5e428eb52e28c1f691ff85d839f3f59f 100644
--- a/pkg/analysis_server/benchmark/integration/input_converter.dart
+++ b/pkg/analysis_server/benchmark/integration/input_converter.dart
@@ -271,8 +271,7 @@ abstract class CommonInputConverter extends Converter<String, Operation> {
  * into a series of operations to be sent to the analysis server.
  * The input stream can be either an instrumenation or log file.
  */
-class InputConverter
-    extends ChunkedConverter<String, Operation, String, Operation> {
+class InputConverter extends Converter<String, Operation> {
 
   final Logger logger = new Logger('InputConverter');