Convert ARRAYSIZE_UNSAFE -> arraysize in base/.

R=thestig@chromium.org
BUG=423134

Review URL: https://codereview.chromium.org/656033009

Cr-Commit-Position: refs/heads/master@{#299835}
scoped_refptr<base::FieldTrial> CreateFieldTrial(
    const std::string& trial_name,
    int total_probability,
    const std::string& default_group_name,
    int* default_group_number) {
  return FieldTrialList::FactoryGetFieldTrial(
      trial_name, total_probability, default_group_name,
      base::FieldTrialList::kNoExpirationYear, 1, 1,
      base::FieldTrial::SESSION_RANDOMIZED, default_group_number);
}

scoped_refptr<base::FieldTrial> CreateFieldTrial(
    const std::string& trial_name,
    int total_probability,
    const std::string& default_group_name,
    int* default_group_number) {
  return FieldTrialList::FactoryGetFieldTrial(
      trial_name, total_probability, default_group_name,
      base::FieldTrialList::kNoExpirationYear, 1, 1,
      base::FieldTrial::SESSION_RANDOMIZED, default_group_number);
}
