And another... :(

sdk/lib/_internal/compiler/implementation/lib/io_patch.dart

Index: sdk/lib/_internal/compiler/implementation/lib/io_patch.dart
diff --git a/sdk/lib/_internal/compiler/implementation/lib/io_patch.dart b/sdk/lib/_internal/compiler/implementation/lib/io_patch.dart
index ed10807eb18285a95cf23ba8e9a1c917d78c9230..9354a6bf4c57eae9da614e01d81c3005e7af69f4 100644
--- a/sdk/lib/_internal/compiler/implementation/lib/io_patch.dart
+++ b/sdk/lib/_internal/compiler/implementation/lib/io_patch.dart
@@ -235,3 +235,12 @@ patch class _WindowsCodePageEncoder {
     throw new UnsupportedError("_WindowsCodePageEncoder._encodeString");
   }
 }
+
+patch class _Filter {
+  patch static _Filter newZLibDeflateFilter(bool gzip, int level) {
+    throw new UnsupportedError("newZLibDeflateFilter");
+  }
+  patch static _Filter newZLibInflateFilter() {
+    throw new UnsupportedError("newZLibInflateFilter");
+  }
+}