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

chrome/test/chromedriver/chrome/util.cc

Index: chrome/test/chromedriver/chrome/util.cc
diff --git a/chrome/test/chromedriver/chrome/util.cc b/chrome/test/chromedriver/chrome/util.cc
index b7f1a5cde097922b65eda5c1f3f4553adcbfb998..02206f372fdc8373907cc168200eb4b35b88ce92 100644
--- a/chrome/test/chromedriver/chrome/util.cc
+++ b/chrome/test/chromedriver/chrome/util.cc
@@ -9,6 +9,6 @@
 
 std::string SerializeValue(const base::Value* value) {
   std::string json;
-  base::JSONWriter::Write(value, &json);
+  base::JSONWriter::Write(*value, &json);
   return json;
 }