Add generic types for strong mode

lib/src/protobuf/field_type.dart

 // 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 protobuf;
 
 bool _isRepeated(int fieldType) => (fieldType & PbFieldType._REPEATED_BIT) != 0;
 
 bool _isRequired(int fieldType) => (fieldType & PbFieldType._REQUIRED_BIT) != 0;
 
 bool _isEnum(int fieldType) =>
     PbFieldType._baseType(fieldType) == PbFieldType._ENUM_BIT;
 
 bool _isGroupOrMessage(int fieldType) =>
     (fieldType & (PbFieldType._GROUP_BIT | PbFieldType._MESSAGE_BIT)) != 0;
 
 /// Defines constants and functions for dealing with fieldType bits.
 class PbFieldType {
-
   /// Returns the base field type without any of the required, repeated
   /// and packed bits.
   static int _baseType(int fieldType) =>
       fieldType & ~(_REQUIRED_BIT | _REPEATED_BIT | _PACKED_BIT);
 
   static MakeDefaultFunc _defaultForType(int type) {
     switch (type) {
       case _OPTIONAL_BOOL:
       case _REQUIRED_BOOL:
         return _BOOL_FALSE;
@@ skipping 29 matching lines @@
       case _OPTIONAL_SFIXED64:
       case _REQUIRED_SFIXED64:
         return _INT_ZERO;
       default:
         return null;
     }
   }
 
   // Closures commonly used by initializers.
   static String _STRING_EMPTY() => '';
-  static List<int> _BYTES_EMPTY() => new PbList(check: _checkInt);
+  static List<int> _BYTES_EMPTY() => new PbList<int>(check: _checkInt);
   static bool _BOOL_FALSE() => false;
   static int _INT_ZERO() => 0;
   static double _DOUBLE_ZERO() => 0.0;
 
   static const int _REQUIRED_BIT = 0x1;
   static const int _REPEATED_BIT = 0x2;
   static const int _PACKED_BIT = 0x4;
 
   static const int _BOOL_BIT = 0x10;
   static const int _BYTES_BIT = 0x20;
@@ skipping 159 matching lines @@
   static const int K6 = _PACKED_INT64;
   static const int KS3 = _PACKED_SINT32;
   static const int KS6 = _PACKED_SINT64;
   static const int KU3 = _PACKED_UINT32;
   static const int KU6 = _PACKED_UINT64;
   static const int KF3 = _PACKED_FIXED32;
   static const int KF6 = _PACKED_FIXED64;
   static const int KSF3 = _PACKED_SFIXED32;
   static const int KSF6 = _PACKED_SFIXED64;
 }