Move variations prefs into the variations component

These prefs are used by variations code that is targeted for componentization.

BUG=382865
TBR=thakis

Review URL: https://codereview.chromium.org/1265423003

Cr-Commit-Position: refs/heads/master@{#343661}
void OverrideUIString(uint32_t hash, const base::string16& string) {
  int resource_id = GetResourceIndex(hash);
  if (resource_id == -1)
    return;

  ui::ResourceBundle::GetSharedInstance().OverrideLocaleStringResource(
      resource_id, string);
}

void OverrideUIString(uint32_t hash, const base::string16& string) {
  int resource_id = GetResourceIndex(hash);
  if (resource_id == -1)
    return;

  ui::ResourceBundle::GetSharedInstance().OverrideLocaleStringResource(
      resource_id, string);
}
