Standardize usage of virtual/override/final in remoting/

remoting/base/auto_thread.h

Index: remoting/base/auto_thread.h
diff --git a/remoting/base/auto_thread.h b/remoting/base/auto_thread.h
index ece36856227cf0a7b3cfe9621ea5ac3f99fab457..9e6baefde076ef4499794985e43a723471675f82 100644
--- a/remoting/base/auto_thread.h
+++ b/remoting/base/auto_thread.h
@@ -55,7 +55,7 @@ class AutoThread : base::PlatformThread::Delegate {
   explicit AutoThread(const char* name);
 
   // Waits for the thread to exit, and then destroys it.
-  virtual ~AutoThread();
+  ~AutoThread() override;
 
   // Starts the thread, running the specified type of MessageLoop.  Returns
   // an AutoThreadTaskRunner through which tasks may be posted to the thread
@@ -83,7 +83,7 @@ class AutoThread : base::PlatformThread::Delegate {
   void JoinAndDeleteThread();
 
   // base::PlatformThread::Delegate methods:
-  virtual void ThreadMain() override;
+  void ThreadMain() override;
 
   // Used to pass data to ThreadMain.
   struct StartupData;