Bluetooth: gather usage metrics

device/bluetooth/bluetooth_adapter_experimental_chromeos.cc

Index: device/bluetooth/bluetooth_adapter_experimental_chromeos.cc
diff --git a/device/bluetooth/bluetooth_adapter_experimental_chromeos.cc b/device/bluetooth/bluetooth_adapter_experimental_chromeos.cc
index 2af93768b637c191cb961d72bf31981d8c4a58a5..0bc15cd905465fec66da9b90dab12424975f213e 100644
--- a/device/bluetooth/bluetooth_adapter_experimental_chromeos.cc
+++ b/device/bluetooth/bluetooth_adapter_experimental_chromeos.cc
@@ -8,6 +8,7 @@
 
 #include "base/bind.h"
 #include "base/logging.h"
+#include "base/metrics/histogram.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
 #include "chromeos/dbus/experimental_bluetooth_adapter_client.h"
 #include "chromeos/dbus/experimental_bluetooth_device_client.h"
@@ -249,6 +250,19 @@ void BluetoothAdapterExperimentalChromeOS::DevicePropertyChanged(
         BluetoothAdapter::Observer, observers_,
         DeviceChanged(this, device_chromeos));
   }
+
+  // UMA connection counting
+  if (property_name == properties->connected.name()) {
+    int count = 0;
+
+    for (DevicesMap::iterator iter = devices_.begin();
+         iter != devices_.end(); ++iter) {
+      if (iter->second->IsConnected())
+        ++count;
+    }
+
+    UMA_HISTOGRAM_COUNTS_100("Bluetooth.ConnectedDeviceCount", count);
+  }
 }
 
 BluetoothDeviceExperimentalChromeOS*