json_schema_compiler: Don't use deprecated ListValue::Append(Value*) overload.

tools/json_schema_compiler/test/test_util.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef TOOLS_JSON_SCHEMA_COMPILER_TEST_TEST_UTIL_H_
 #define TOOLS_JSON_SCHEMA_COMPILER_TEST_TEST_UTIL_H_
 
 #include <memory>
 
 #include "base/strings/string_piece.h"
@@ skipping 16 matching lines @@
   arr.push_back(b);
   return arr;
 }
 template <typename T>
 std::vector<T> Vector(const T& a, const T& b, const T& c) {
   std::vector<T> arr = Vector(a, b);
   arr.push_back(c);
   return arr;
 }
 
+// TODO(dcheng): These various helpers should all take std::unique_ptr
+// arguments. See https://crbug.com/581865.
 std::unique_ptr<base::ListValue> List(base::Value* a);
 std::unique_ptr<base::ListValue> List(base::Value* a, base::Value* b);
 std::unique_ptr<base::ListValue> List(base::Value* a,
                                       base::Value* b,
                                       base::Value* c);
 
 std::unique_ptr<base::DictionaryValue> Dictionary(const std::string& ak,
                                                   base::Value* av);
 std::unique_ptr<base::DictionaryValue> Dictionary(const std::string& ak,
                                                   base::Value* av,
                                                   const std::string& bk,
                                                   base::Value* bv);
 std::unique_ptr<base::DictionaryValue> Dictionary(const std::string& ak,
                                                   base::Value* av,
                                                   const std::string& bk,
                                                   base::Value* bv,
                                                   const std::string& ck,
                                                   base::Value* cv);
 
 }  // namespace test_util
 }  // namespace json_schema_compiler
 
 #endif  // TOOLS_JSON_SCHEMA_COMPILER_TEST_TEST_UTIL_H_