Standardize usage of virtual/override/final in content/

content/gpu/gpu_child_thread.h

Index: content/gpu/gpu_child_thread.h
diff --git a/content/gpu/gpu_child_thread.h b/content/gpu/gpu_child_thread.h
index b034a8f4460e6939a909f85ab95abf7c1a9c5668..cddbe00c9cef96aa63bd76ea9d932b38df2e8fa4 100644
--- a/content/gpu/gpu_child_thread.h
+++ b/content/gpu/gpu_child_thread.h
@@ -45,16 +45,16 @@ class GpuChildThread : public ChildThread {
   // For single-process mode.
   explicit GpuChildThread(const std::string& channel_id);
 
-  virtual ~GpuChildThread();
+  ~GpuChildThread() override;
 
-  virtual void Shutdown() override;
+  void Shutdown() override;
 
   void Init(const base::Time& process_start_time);
   void StopWatchdog();
 
   // ChildThread overrides.
-  virtual bool Send(IPC::Message* msg) override;
-  virtual bool OnControlMessageReceived(const IPC::Message& msg) override;
+  bool Send(IPC::Message* msg) override;
+  bool OnControlMessageReceived(const IPC::Message& msg) override;
 
  private:
   // Message handlers.