Upgrade jsoncpp to 1.9.4

Bug: 170642246
Change-Id: Id1fae5a1b6421117f923c616718ee4b3571231e0
diff --git a/src/test_lib_json/fuzz.h b/src/test_lib_json/fuzz.h
new file mode 100644
index 0000000..0816d27
--- /dev/null
+++ b/src/test_lib_json/fuzz.h
@@ -0,0 +1,14 @@
+// Copyright 2007-2010 The JsonCpp Authors
+// Distributed under MIT license, or public domain if desired and
+// recognized in your jurisdiction.
+// See file LICENSE for detail or copy at http://jsoncpp.sourceforge.net/LICENSE
+
+#ifndef FUZZ_H_INCLUDED
+#define FUZZ_H_INCLUDED
+
+#include <cstddef>
+#include <stdint.h>
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size);
+
+#endif // ifndef FUZZ_H_INCLUDED