Increase Web Bluetooth device scanning duration

content/browser/bluetooth/bluetooth_device_chooser_controller.cc

Index: content/browser/bluetooth/bluetooth_device_chooser_controller.cc
diff --git a/content/browser/bluetooth/bluetooth_device_chooser_controller.cc b/content/browser/bluetooth/bluetooth_device_chooser_controller.cc
index 082d1e8b42f0aad21f6cd7546f85663df1f7df26..83f18f896104cd256bce1ef86629d5f7958dcb85 100644
--- a/content/browser/bluetooth/bluetooth_device_chooser_controller.cc
+++ b/content/browser/bluetooth/bluetooth_device_chooser_controller.cc
@@ -10,6 +10,7 @@
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "content/browser/bluetooth/bluetooth_blacklist.h"
@@ -54,7 +55,7 @@ constexpr size_t kMaxLengthForDeviceName =
     29;  // max length of device name in filter.
 
 // The duration of a Bluetooth Scan in seconds.
-constexpr int kScanDuration = 10;
+constexpr int kScanDuration = 60;
 constexpr int kTestScanDuration = 0;
 
 void LogRequestDeviceOptions(
@@ -197,15 +198,17 @@ UMARequestDeviceOutcome OutcomeFromChooserEvent(BluetoothChooser::Event event) {
       NOTREACHED();
       return UMARequestDeviceOutcome::SUCCESS;
     case BluetoothChooser::Event::RESCAN:
-      // Rescanning doesn't result in a IPC message for the request being sent
-      // so no need to histogram it.
-      NOTREACHED();
-      return UMARequestDeviceOutcome::SUCCESS;
+      return UMARequestDeviceOutcome::BLUETOOTH_CHOOSER_RESCAN;
   }
   NOTREACHED();
   return UMARequestDeviceOutcome::SUCCESS;
 }
 
+void RecordScanningDuration(const base::TimeDelta& duration) {
+  UMA_HISTOGRAM_LONG_TIMES("Bluetooth.Web.RequestDevice.ScanningDuration",
+                           duration);
+}
+
 }  // namespace
 
 BluetoothDeviceChooserController::BluetoothDeviceChooserController(
@@ -232,6 +235,12 @@ BluetoothDeviceChooserController::BluetoothDeviceChooserController(
 }
 
 BluetoothDeviceChooserController::~BluetoothDeviceChooserController() {
+  if (scanning_start_time_) {
+    RecordScanningDuration(base::TimeTicks::Now() -
+                           scanning_start_time_.value());
+    scanning_start_time_.reset();

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

Why do we need to clear the optional<timer> when destructing? 

[juncai, 2016/11/17 22:44:41]

Done.

+  }
+
   if (chooser_) {
     DCHECK(!error_callback_.is_null());
     error_callback_.Run(blink::mojom::WebBluetoothResult::CHOOSER_CANCELLED);
@@ -439,6 +448,8 @@ void BluetoothDeviceChooserController::StartDeviceDiscovery() {
     return;
   }
 
+  scanning_start_time_ = base::TimeTicks::Now();
+
   chooser_->ShowDiscoveryState(BluetoothChooser::DiscoveryState::DISCOVERING);
   adapter_->StartDiscoverySessionWithFilter(
       ComputeScanFilter(options_->filters),
@@ -486,6 +497,7 @@ void BluetoothDeviceChooserController::OnBluetoothChooserEvent(
 
   switch (event) {
     case BluetoothChooser::Event::RESCAN:
+      RecordRequestDeviceOutcome(OutcomeFromChooserEvent(event));
       PopulateConnectedDevices();
       DCHECK(chooser_);
       StartDeviceDiscovery();