[EasyUnlock] Force user to enter their password after 20 hours.

components/proximity_auth/proximity_auth_pref_manager.cc

Index: components/proximity_auth/proximity_auth_pref_manager.cc
diff --git a/components/proximity_auth/proximity_auth_pref_manager.cc b/components/proximity_auth/proximity_auth_pref_manager.cc
index 7d2dbd6937b4b17e2a23274b30adc64242f660ef..c8c637c0cf2b8869ce7a8c40e334d6f952b7801a 100644
--- a/components/proximity_auth/proximity_auth_pref_manager.cc
+++ b/components/proximity_auth/proximity_auth_pref_manager.cc
@@ -24,6 +24,8 @@ ProximityAuthPrefManager::~ProximityAuthPrefManager() {}
 
 // static
 void ProximityAuthPrefManager::RegisterPrefs(PrefRegistrySimple* registry) {
+  registry->RegisterInt64Pref(prefs::kProximityAuthLastPasswordEntryTimestampMs,
+                              0L);
   registry->RegisterDictionaryPref(prefs::kProximityAuthRemoteBleDevices);
 }
 
@@ -103,6 +105,16 @@ bool ProximityAuthPrefManager::RemoveDeviceWithPublicKey(
     const std::string& public_key) {
   return RemoveDeviceWithAddress(GetDeviceAddress(public_key));
 }
+void ProximityAuthPrefManager::SetLastPasswordEntryTimestampMs(
+    int64_t timestamp_ms) {
+  pref_service_->SetInt64(prefs::kProximityAuthLastPasswordEntryTimestampMs,
+                          timestamp_ms);
+}
+
+int64_t ProximityAuthPrefManager::GetLastPasswordEntryTimestampMs() const {
+  return pref_service_->GetInt64(
+      prefs::kProximityAuthLastPasswordEntryTimestampMs);
+}
 
 const base::DictionaryValue* ProximityAuthPrefManager::GetRemoteBleDevices()
     const {