web build fail

[Yonkers]

version: ^0.2.2-pre

part of error:

 ../../../.pub-cache/hosted/pub.flutter-io.cn/win32-2.1.3/lib/src/com/UserDataPaths.dart:107:32:
  Error: 'IntPtr' isn't a type.
      final retValuePtr = calloc<IntPtr>();
                                 ^^^^^^
  ../../../.pub-cache/hosted/pub.flutter-io.cn/win32-2.1.3/lib/src/com/UserDataPaths.dart:110:26:
  Error: 'NativeFunction' isn't a type.
        final hr = Pointer<NativeFunction<_get_CameraRoll_Native>>.fromAddress(
                           ^^^^^^^^^^^^^^
  ../../../.pub-cache/hosted/pub.flutter-io.cn/win32-2.1.3/lib/src/com/UserDataPaths.dart:110:18:
  Error: Method not found: 'Pointer.fromAddress'.
        final hr = Pointer<NativeFunction<_get_CameraRoll_Native>>.fromAddress(
                   ^^^^^^^^^^^
  ../../../.pub-cache/hosted/pub.flutter-io.cn/win32-2.1.3/lib/src/com/UserDataPaths.dart:123:32:
  Error: 'IntPtr' isn't a type.
      final retValuePtr = calloc<IntPtr>();
                                 ^^^^^^