Add timeout task to U2F HID state machine

device/u2f/u2f_hid_device.h

Index: device/u2f/u2f_hid_device.h
diff --git a/device/u2f/u2f_hid_device.h b/device/u2f/u2f_hid_device.h
index 527c0b30177d73554b328c108745ee2abbe4c3ad..84694f4ba295e10fe010191d2b4bbda4d8f7fcd6 100644
--- a/device/u2f/u2f_hid_device.h
+++ b/device/u2f/u2f_hid_device.h
@@ -7,6 +7,7 @@
 
 #include <list>
 
+#include "base/cancelable_callback.h"
 #include "device/hid/hid_service.h"
 #include "u2f_device.h"
 
@@ -23,7 +24,7 @@ class HidDeviceInfo;
 class U2fHidDevice : public U2fDevice {
  public:
   U2fHidDevice(scoped_refptr<HidDeviceInfo>);
-  ~U2fHidDevice();
+  ~U2fHidDevice() final;
 
   // Send a U2f command to this device
   void DeviceTransact(std::unique_ptr<U2fApduCommand> command,
@@ -85,8 +86,13 @@ class U2fHidDevice : public U2fDevice {
   void OnWink(const WinkCallback& callback,
               bool success,
               std::unique_ptr<U2fMessage> response);
+  void ArmTimeout(const DeviceCallback& callback);
+  void OnTimeout(const DeviceCallback& callback);
+  void OnDeviceTransact(bool success,
+                        std::unique_ptr<U2fApduResponse> response);
 
   State state_;
+  base::CancelableClosure timeout_callback_;
   std::list<std::pair<std::unique_ptr<U2fApduCommand>, DeviceCallback>>
       pending_transactions_;
   scoped_refptr<HidDeviceInfo> device_info_;