Convert HidDeviceInfo from a struct to a refcounted class.

device/hid/hid_service_mac.h

Index: device/hid/hid_service_mac.h
diff --git a/device/hid/hid_service_mac.h b/device/hid/hid_service_mac.h
index bfb58bdfc6cdef9bbd76a24f80903b2ce40db91b..11725d2fbe4f8710905d2db1e476cd6a762eaf39 100644
--- a/device/hid/hid_service_mac.h
+++ b/device/hid/hid_service_mac.h
@@ -40,6 +40,9 @@ class HidServiceMac : public HidService {
   void AddDevices();
   void RemoveDevices();
 
+  static scoped_refptr<device::HidDeviceInfo> CreateDeviceInfo(
+      io_service_t device);
+
   // Platform notification port.
   IONotificationPortRef notify_port_;
   base::mac::ScopedIOObject<io_iterator_t> devices_added_iterator_;