Remove outdated devices from Android device chooser

device/bluetooth/bluetooth_low_energy_device_mac.mm

Index: device/bluetooth/bluetooth_low_energy_device_mac.mm
diff --git a/device/bluetooth/bluetooth_low_energy_device_mac.mm b/device/bluetooth/bluetooth_low_energy_device_mac.mm
index b8c47f4552fecb6d30312d02bb47c422c36274ea..54249747a52c225fa87595ab5d75eb09e4f8211f 100644
--- a/device/bluetooth/bluetooth_low_energy_device_mac.mm
+++ b/device/bluetooth/bluetooth_low_energy_device_mac.mm
@@ -46,7 +46,7 @@ BluetoothLowEnergyDeviceMac::~BluetoothLowEnergyDeviceMac() {
 
 void BluetoothLowEnergyDeviceMac::Update(NSDictionary* advertisement_data,
                                          int rssi) {
-  last_update_time_.reset([[NSDate date] retain]);
+  UpdateTimestamp();
   rssi_ = rssi;
   NSNumber* connectable =
       [advertisement_data objectForKey:CBAdvertisementDataIsConnectable];
@@ -218,10 +218,6 @@ void BluetoothLowEnergyDeviceMac::ConnectToServiceInsecurely(
   NOTIMPLEMENTED();
 }
 
-NSDate* BluetoothLowEnergyDeviceMac::GetLastUpdateTime() const {
-  return last_update_time_.get();
-}
-
 std::string BluetoothLowEnergyDeviceMac::GetDeviceName() const {
   return base::SysNSStringToUTF8([peripheral_ name]);
 }