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

net/http/http_server_properties_manager_unittest.cc

Index: net/http/http_server_properties_manager_unittest.cc
diff --git a/net/http/http_server_properties_manager_unittest.cc b/net/http/http_server_properties_manager_unittest.cc
index 7ab6ef064361b00f03040102ad08df0fe2edd666..414613cda42fdda2c19118e134cb4b9fb0a2b5d8 100644
--- a/net/http/http_server_properties_manager_unittest.cc
+++ b/net/http/http_server_properties_manager_unittest.cc
@@ -708,7 +708,7 @@ TEST_F(HttpServerPropertiesManagerTest, UpdateCacheWithPrefs) {
   ASSERT_NE(nullptr, http_server_properties);
   std::string preferences_json;
   EXPECT_TRUE(
-      base::JSONWriter::Write(http_server_properties, &preferences_json));
+      base::JSONWriter::Write(*http_server_properties, &preferences_json));
   EXPECT_EQ(expected_json, preferences_json);
 }