Remove outdated devices from Android device chooser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 dea3593ff1e0d53d1668b49c16b38e246f4bf3f5..8621c27d5dd6af5a58ba686c7d3651a25c1f0510 100644
--- a/device/bluetooth/bluetooth_adapter.cc
+++ b/device/bluetooth/bluetooth_adapter.cc
@@ -345,6 +345,38 @@ 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())
+      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);
+
+    FOR_EACH_OBSERVER(BluetoothAdapter::Observer, observers_,
+                      DeviceRemoved(this, device));
+    removed_devices.insert(it->first);
+  }
+
+  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) {
@@ -361,4 +393,8 @@ void BluetoothAdapter::RecordBluetoothDiscoverySessionStopOutcome(
       static_cast<int>(UMABluetoothDiscoverySessionOutcome::COUNT));
 }
 
+// static
+const base::TimeDelta BluetoothAdapter::timeoutSec =
+    base::TimeDelta::FromSeconds(30);

[scheib, 2016/04/07 22:05:02]

Why 30? Mac was using 180.

[perja, 2016/04/08 07:47:35]

Only reason for this was that we thought 180 seconds was a too long timeout when
you turn off a device or if it is out of range. But maybe it isn't a use case we
should consider too much (I tested with 3 Mio Playbulbs - turning them on/off).
After all the purpose of the cache is to make it faster to populate the device
chooser. What do you think?

+
 }  // namespace device