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

components/webcrypto/test/test_helpers.cc

Index: components/webcrypto/test/test_helpers.cc
diff --git a/components/webcrypto/test/test_helpers.cc b/components/webcrypto/test/test_helpers.cc
index 76da7faa40579ceb53abdfbcc765084a5069b5bd..8e24c95f32485e535291d5966f647c67860f6a8f 100644
--- a/components/webcrypto/test/test_helpers.cc
+++ b/components/webcrypto/test/test_helpers.cc
@@ -168,7 +168,7 @@ std::vector<uint8_t> MakeJsonVector(const std::string& json_string) {
 
 std::vector<uint8_t> MakeJsonVector(const base::DictionaryValue& dict) {
   std::string json;
-  base::JSONWriter::Write(&dict, &json);
+  base::JSONWriter::Write(dict, &json);
   return MakeJsonVector(json);
 }