Refactor chromedriver's script execution to reduce amount of custom Value parsing.

chrome/test/webdriver/utility_functions.cc

-// Copyright (c) 2011 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.
-
-#include "chrome/test/webdriver/utility_functions.h"
-
-#include "base/basictypes.h"
-#include "base/format_macros.h"
-#include "base/json/json_writer.h"
-#include "base/rand_util.h"
-#include "base/stringprintf.h"
-#include "base/values.h"
-
-namespace webdriver {
-
-std::string GenerateRandomID() {
-  uint64 msb = base::RandUint64();
-  uint64 lsb = base::RandUint64();
-  return base::StringPrintf("%016" PRIx64 "%016" PRIx64, msb, lsb);
-}
-
-std::string JsonStringify(const Value* value) {
-  std::string json;
-  base::JSONWriter::Write(value, false, &json);
-  return json;
-}
-
-}  // namespace webdriver