Add listener for AdapterDiscoveringChanged on BT chooser-controller

content/browser/bluetooth/bluetooth_device_chooser_controller.h

Index: content/browser/bluetooth/bluetooth_device_chooser_controller.h
diff --git a/content/browser/bluetooth/bluetooth_device_chooser_controller.h b/content/browser/bluetooth/bluetooth_device_chooser_controller.h
index 500d31b144c125243d9ff0417a2b8e8a25aa9511..41f551592a75863888756166ceea4adb0f0a49e4 100644
--- a/content/browser/bluetooth/bluetooth_device_chooser_controller.h
+++ b/content/browser/bluetooth/bluetooth_device_chooser_controller.h
@@ -78,6 +78,10 @@ class CONTENT_EXPORT BluetoothDeviceChooserController final {
   // that the adapter changed states.
   void AdapterPoweredChanged(bool powered);
 
+  // Stops the discovery session and notifies the chooser
+  // when discovery stops accidentally.
+  void AdapterDiscoveringChanged(bool discovering);
+
   // Received Signal Strength Indicator (RSSI) is a measurement of the power
   // present in a received radio signal.
   static int CalculateSignalStrengthLevel(int8_t rssi);