Standardize usage of virtual/override/final specifiers in device/.

device/hid/hid_connection_linux.cc

Index: device/hid/hid_connection_linux.cc
diff --git a/device/hid/hid_connection_linux.cc b/device/hid/hid_connection_linux.cc
index 47ae82513c7060b92cc945e7bcaefcc3f4598b18..27975e2eb4a610b4d4e11b8f9c35cab0b6eb1a51 100644
--- a/device/hid/hid_connection_linux.cc
+++ b/device/hid/hid_connection_linux.cc
@@ -43,7 +43,7 @@ class HidConnectionLinux::Helper : public base::MessagePumpLibevent::Watcher {
     has_report_id_ = device_info.has_report_id;
   }
 
-  virtual ~Helper() { DCHECK(thread_checker_.CalledOnValidThread()); }
+  ~Helper() override { DCHECK(thread_checker_.CalledOnValidThread()); }
 
   // Starts the FileDescriptorWatcher that reads input events from the device.
   // Must be called on a thread that has a base::MessageLoopForIO. The helper