[update_engine] Update to use not-hideously-old logging API from chrome

prefs.cc

 // Copyright (c) 2010 The Chromium OS 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 "update_engine/prefs.h"
 
 #include "base/file_util.h"
 #include "base/logging.h"
+#include "base/string_number_conversions.h"
 #include "base/string_util.h"
 #include "update_engine/utils.h"
 
 using std::string;
 
 namespace chromeos_update_engine {
 
 const char kPrefsLastActivePingDay[] = "last-active-ping-day";
 const char kPrefsLastRollCallPingDay[] = "last-roll-call-ping-day";
 
@@ skipping 19 matching lines @@
   TEST_AND_RETURN_FALSE(
       file_util::WriteFile(filename, value.data(), value.size()) ==
       static_cast<int>(value.size()));
   return true;
 }
 
 bool Prefs::GetInt64(const string& key, int64_t* value) {
   string str_value;
   TEST_AND_RETURN_FALSE(GetString(key, &str_value));
   TrimWhitespaceASCII(str_value, TRIM_ALL, &str_value);
-  TEST_AND_RETURN_FALSE(StringToInt64(str_value, value));
+  TEST_AND_RETURN_FALSE(base::StringToInt64(str_value, value));
   return true;
 }
 
 bool Prefs::SetInt64(const string& key, const int64_t value) {
-  return SetString(key, Int64ToString(value));
+  return SetString(key, base::Int64ToString(value));
 }
 
 bool Prefs::GetFileNameForKey(const std::string& key, FilePath* filename) {
   // Allows only non-empty keys containing [A-Za-z0-9_-].
   TEST_AND_RETURN_FALSE(!key.empty());
   for (size_t i = 0; i < key.size(); ++i) {
     char c = key.at(i);
     TEST_AND_RETURN_FALSE(IsAsciiAlpha(c) || IsAsciiDigit(c) ||
                           c == '_' || c == '-');
   }
   *filename = prefs_dir_.Append(key);
   return true;
 }
 
 }  // namespace chromeos_update_engine