[Win] Add option to reauthenticate the OS user before revealing passwords.

chrome/common/pref_names.cc

Index: chrome/common/pref_names.cc
diff --git a/chrome/common/pref_names.cc b/chrome/common/pref_names.cc
index 0e5c3f761c83755f271dd35456f5dfcc5393bee1..0184ceb6d98ff8e1d90963211d18fb9c42c096e5 100644
--- a/chrome/common/pref_names.cc
+++ b/chrome/common/pref_names.cc
@@ -2614,4 +2614,13 @@ const char kNetworkTimeMapping[] = "profile.network_time_mapping";
 const char kPartnerBookmarkMappings[] = "partnerbookmarks.mappings";
 #endif
 
+#if defined(OS_WIN)
+// Whether the password was blank, only valid if OS password was last changed
+// on or before the value contained in kOsPasswordLastChanged.
+const char kOsPasswordBlank[] = "password_manager.os_password_blank";
+
+// The number of seconds since epoch that the OS password was last changed.
+const char kOsPasswordLastChanged[] =
+    "password_manager.os_password_last_changed";
+#endif
 }  // namespace prefs