Remove outdated devices from Android device chooser

device/bluetooth/bluetooth_adapter.cc

Index: device/bluetooth/bluetooth_adapter.cc
diff --git a/device/bluetooth/bluetooth_adapter.cc b/device/bluetooth/bluetooth_adapter.cc
index 09127f981cb48ec266570c74a803285da6f33141..073dd81c7aca8503e12ecd9bce33a35e3768263f 100644
--- a/device/bluetooth/bluetooth_adapter.cc
+++ b/device/bluetooth/bluetooth_adapter.cc
@@ -365,6 +365,38 @@ BluetoothAdapter::GetMergedDiscoveryFilterHelper(
   return result;
 }
 
+void BluetoothAdapter::RemoveTimedOutDevices() {
+  std::set<std::string> removed_devices;
+  for (DevicesMap::const_iterator it = devices_.begin(); it != devices_.end();
+       ++it) {
+    BluetoothDevice* device = it->second;
+
+    if (device->IsPaired() || device->IsConnected() ||
+        device->IsGattConnected())
+      continue;
+
+    base::Time last_update_time = device->GetLastUpdateTime();
+
+    bool device_expired =
+        (base::Time::NowFromSystemTime() - last_update_time) > timeoutSec;
+    VLOG(1) << "device: " << device->GetAddress()
+            << ", last_update: " << last_update_time
+            << ", exp: " << device_expired;
+
+    if (!device_expired)
+      continue;
+    removed_devices.insert(it->first);

[ortuno, 2016/06/22 17:23:11]

nit: I would change removed_devices to be a std::vector<std::unique_ptr> and
call 

removed_devices.push_back(devices_.take_and_erase(it));

This way if someone calls GetDevices inside DeviceRemoved the removed device is
not included.

[perja, 2016/06/23 14:31:25]

I used a slightly different approach. Please take a look.

+
+    FOR_EACH_OBSERVER(BluetoothAdapter::Observer, observers_,
+                      DeviceRemoved(this, device));
+  }
+
+  for (const std::string& device_address : removed_devices) {
+    size_t num_removed = devices_.erase(device_address);
+    DCHECK_EQ(num_removed, 1U);
+  }
+}
+
 // static
 void BluetoothAdapter::RecordBluetoothDiscoverySessionStartOutcome(
     UMABluetoothDiscoverySessionOutcome outcome) {
@@ -381,4 +413,8 @@ void BluetoothAdapter::RecordBluetoothDiscoverySessionStopOutcome(
       static_cast<int>(UMABluetoothDiscoverySessionOutcome::COUNT));
 }
 
+// static
+const base::TimeDelta BluetoothAdapter::timeoutSec =
+    base::TimeDelta::FromSeconds(180);
+
 }  // namespace device