Refactor windows dependency out of UpdaterState class.

components/update_client/updater_state.h

Index: components/update_client/updater_state.h
diff --git a/components/update_client/updater_state.h b/components/update_client/updater_state.h
index 11f2fa985531f1b7d56967f937f648ee1f71020e..ea8b64e0e225daf3e2dddaa68ed25f3ccb9e2760 100644
--- a/components/update_client/updater_state.h
+++ b/components/update_client/updater_state.h
@@ -47,8 +47,7 @@ class UpdaterState {
   static bool IsEnterpriseManaged();
   static base::Time GetUpdaterLastStartedAU(bool is_machine);
   static base::Time GetUpdaterLastChecked(bool is_machine);
-  static base::Time GetUpdaterTimeValue(bool is_machine,
-                                        const wchar_t* value_name);
+
   static int GetUpdatePolicy();
 
   static std::string NormalizeTimeDelta(const base::TimeDelta& delta);