Add UMA for the number of devices in the chooser when a device is paired

content/browser/bluetooth/bluetooth_device_chooser_controller.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/bluetooth/bluetooth_device_chooser_controller.h"
 
 #include <set>
 #include <string>
 #include <unordered_set>
 
@@ skipping 411 matching lines @@
 }
 
 void BluetoothDeviceChooserController::AddFilteredDevice(
     const device::BluetoothDevice& device) {
   base::Optional<std::string> device_name = device.GetName();
   if (chooser_.get()) {
     if (options_->accept_all_devices ||
         MatchesFilters(device_name ? &device_name.value() : nullptr,
                        device.GetUUIDs(), options_->filters)) {
       base::Optional<int8_t> rssi = device.GetInquiryRSSI();
+      std::string device_id = device.GetAddress();
+      device_ids_.insert(device_id);

[Reilly Grant (use Gerrit), 2016/12/19 20:52:17]

I was going to note that you should call device_ids_.erase() whenever you call
BluetoothChooser::RemoveDevice() but then noticed that there is no code that
calls that function, so I suggest removing it in a follow-up patch.

[juncai, 2016/12/19 22:16:13]

Thanks! I filed a bug for it:
https://bugs.chromium.org/p/chromium/issues/detail?id=675720

       chooser_->AddOrUpdateDevice(
-          device.GetAddress(), !!device.GetName() /* should_update_name */,
+          device_id, !!device.GetName() /* should_update_name */,
           device.GetNameForDisplay(), device.IsGattConnected(),
           web_bluetooth_service_->IsDevicePaired(device.GetAddress()),
           rssi ? CalculateSignalStrengthLevel(rssi.value()) : -1);
     }
   }
 }
 
 void BluetoothDeviceChooserController::AdapterPoweredChanged(bool powered) {
   if (!powered && discovery_session_.get()) {
     StopDiscoverySession(std::move(discovery_session_));
@@ skipping 50 matching lines @@
 
 void BluetoothDeviceChooserController::StartDeviceDiscovery() {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
   if (discovery_session_.get() && discovery_session_->IsActive()) {
     // Already running; just increase the timeout.
     discovery_session_timer_.Reset();
     return;
   }
 
+  device_ids_.clear();
+
   scanning_start_time_ = base::TimeTicks::Now();
 
   chooser_->ShowDiscoveryState(BluetoothChooser::DiscoveryState::DISCOVERING);
   adapter_->StartDiscoverySessionWithFilter(
       ComputeScanFilter(options_->filters),
       base::Bind(
           &BluetoothDeviceChooserController::OnStartDiscoverySessionSuccess,
           weak_ptr_factory_.GetWeakPtr()),
       base::Bind(
           &BluetoothDeviceChooserController::OnStartDiscoverySessionFailed,
@@ skipping 67 matching lines @@
       VLOG(1) << "Adapter Off Help link pressed.";
       RecordRequestDeviceOutcome(OutcomeFromChooserEvent(event));
       PostErrorCallback(blink::mojom::WebBluetoothResult::CHOOSER_CANCELLED);
       break;
     case BluetoothChooser::Event::SHOW_NEED_LOCATION_HELP:
       VLOG(1) << "Need Location Help link pressed.";
       RecordRequestDeviceOutcome(OutcomeFromChooserEvent(event));
       PostErrorCallback(blink::mojom::WebBluetoothResult::CHOOSER_CANCELLED);
       break;
     case BluetoothChooser::Event::SELECTED:
+      RecordNumOfDevices(options_->accept_all_devices, device_ids_.size());
       // RecordRequestDeviceOutcome is called in the callback, because the
       // device may have vanished.
       PostSuccessCallback(device_address);
       break;
   }
   // Close chooser.
   chooser_.reset();
 }
 
 void BluetoothDeviceChooserController::PostSuccessCallback(
     const std::string& device_address) {
   if (!base::ThreadTaskRunnerHandle::Get()->PostTask(
           FROM_HERE,
           base::Bind(success_callback_, base::Passed(std::move(options_)),
                      device_address))) {
     LOG(WARNING) << "No TaskRunner.";
   }
 }
 
 void BluetoothDeviceChooserController::PostErrorCallback(
     blink::mojom::WebBluetoothResult error) {
   if (!base::ThreadTaskRunnerHandle::Get()->PostTask(
           FROM_HERE, base::Bind(error_callback_, error))) {
     LOG(WARNING) << "No TaskRunner.";
   }
 }
 
 }  // namespace content