BT adapter is switched to initial state after HID screen if no BT devices connected.

chrome/browser/ui/webui/chromeos/login/hid_detection_screen_handler.h

 // Copyright 2014 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.
 
 #ifndef CHROME_BROWSER_UI_WEBUI_CHROMEOS_LOGIN_HID_DETECTION_SCREEN_HANDLER_H_
 #define CHROME_BROWSER_UI_WEBUI_CHROMEOS_LOGIN_HID_DETECTION_SCREEN_HANDLER_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 150 matching lines @@
       scoped_ptr<device::BluetoothDiscoverySession> discovery_session);
 
   // Called by device::BluetoothAdapter in response to a failure to
   // initiate a discovery session.
   void FindDevicesError();
 
   // Called by device::BluetoothAdapter in response to a failure to
   // power BT adapter.
   void SetPoweredError();
 
+  // Called by device::BluetoothAdapter in response to a failure to
+  // power off BT adapter.
+  void SetPoweredOffError();
+
   // Called for revision of active devices. If current-placement is available
   // for mouse or keyboard device, sets one of active devices as current or
   // tries to connect some BT device if no appropriate devices are connected.
   void UpdateDevices();
 
   // Tries to connect some BT devices if no type-appropriate devices are
   // connected.
   void UpdateBTDevices();
 
   // Tries to connect given BT device.
@@ skipping 22 matching lines @@
   InputDeviceInfo::Type pointing_device_connect_type_;
 
   // Current keyboard device, if any.
   std::string keyboard_device_name_;
   std::string keyboard_device_id_;
   bool keyboard_is_pairing_;
   InputDeviceInfo::Type keyboard_device_connect_type_;
 
   bool switch_on_adapter_when_ready_;
 
+  // State of BT adapter before screen-initiated changes.
+  scoped_ptr<bool> adapter_initially_powered_;
+
   base::WeakPtrFactory<HIDDetectionScreenHandler> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(HIDDetectionScreenHandler);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_UI_WEBUI_CHROMEOS_LOGIN_HID_DETECTION_SCREEN_HANDLER_H_