Make core libraries use generic method syntax.

runtime/lib/convert_patch.dart

Index: runtime/lib/convert_patch.dart
diff --git a/runtime/lib/convert_patch.dart b/runtime/lib/convert_patch.dart
index 25a8dc51190c1ae1fbb3203724e30de7cb0c6b27..d2ce1a354d2ff96f4c00ac4e6093b14277555500 100644
--- a/runtime/lib/convert_patch.dart
+++ b/runtime/lib/convert_patch.dart
@@ -23,8 +23,8 @@ import "dart:_internal" show POWERS_OF_TEN;
 
 @patch class Utf8Decoder {
   @patch
-  Converter<List<int>, dynamic/*=T*/> fuse/*<T>*/(
-      Converter<String, dynamic/*=T*/> next) {
+  Converter<List<int>, T> fuse<T>(
+      Converter<String, T> next) {
     if (next is JsonDecoder) {
       return new _JsonUtf8Decoder(next._reviver, this._allowMalformed)
           as dynamic/*=Converter<List<int>, T>*/;