Convert JsonWriter::Write to taking a const ref for the in-param

chrome/browser/local_discovery/privet_http_unittest.cc

Index: chrome/browser/local_discovery/privet_http_unittest.cc
diff --git a/chrome/browser/local_discovery/privet_http_unittest.cc b/chrome/browser/local_discovery/privet_http_unittest.cc
index f8d5dbe539b9f51fc9b38a73b8a92b89891b2b89..9fe8500dd32054cbe6fc7555858dece1c7cac01a 100644
--- a/chrome/browser/local_discovery/privet_http_unittest.cc
+++ b/chrome/browser/local_discovery/privet_http_unittest.cc
@@ -222,7 +222,7 @@ std::string NormalizeJson(const std::string& json) {
   std::string result = json;
   scoped_ptr<base::Value> value(base::JSONReader::Read(result));
   DCHECK(value);
-  base::JSONWriter::Write(value.get(), &result);
+  base::JSONWriter::Write(*value, &result);
   return result;
 }