Standardize usage of virtual/override/final in media/

media/base/user_input_monitor_mac.cc

Index: media/base/user_input_monitor_mac.cc
diff --git a/media/base/user_input_monitor_mac.cc b/media/base/user_input_monitor_mac.cc
index c157ed470cd85af39fbc44895f9a81bd8a8d6d69..e469cbd65acb1b79063693d72ba5558d92b95b93 100644
--- a/media/base/user_input_monitor_mac.cc
+++ b/media/base/user_input_monitor_mac.cc
@@ -12,15 +12,15 @@ namespace {
 class UserInputMonitorMac : public UserInputMonitor {
  public:
   UserInputMonitorMac();
-  virtual ~UserInputMonitorMac();
+  ~UserInputMonitorMac() override;
 
-  virtual size_t GetKeyPressCount() const override;
+  size_t GetKeyPressCount() const override;
 
  private:
-  virtual void StartKeyboardMonitoring() override;
-  virtual void StopKeyboardMonitoring() override;
-  virtual void StartMouseMonitoring() override;
-  virtual void StopMouseMonitoring() override;
+  void StartKeyboardMonitoring() override;
+  void StopKeyboardMonitoring() override;
+  void StartMouseMonitoring() override;
+  void StopMouseMonitoring() override;
 
   DISALLOW_COPY_AND_ASSIGN(UserInputMonitorMac);
 };