mac: Prepare for -Wunused-functions.

chrome/browser/metrics/variations/variations_service.cc

Index: chrome/browser/metrics/variations/variations_service.cc
diff --git a/chrome/browser/metrics/variations/variations_service.cc b/chrome/browser/metrics/variations/variations_service.cc
index 03da6723ebd8bd59497d4f3815ab6cb0f455ebaa..a761da9d6d10a5bb70c0fc51efbb9e0c1cd3a80d 100644
--- a/chrome/browser/metrics/variations/variations_service.cc
+++ b/chrome/browser/metrics/variations/variations_service.cc
@@ -108,11 +108,6 @@ std::string GetPlatformString() {
 #endif
 }
 
-// Converts |date_time| in Study date format to base::Time.
-base::Time ConvertStudyDateToBaseTime(int64 date_time) {
-  return base::Time::UnixEpoch() + base::TimeDelta::FromSeconds(date_time);
-}
-
 // Gets the restrict parameter from |local_state| or from Chrome OS settings in
 // the case of that platform.
 std::string GetRestrictParameterPref(PrefService* local_state) {