Update {virtual,override,final} to follow C++11 style in media, round 2.

media/video/capture/linux/video_capture_device_chromeos.cc

Index: media/video/capture/linux/video_capture_device_chromeos.cc
diff --git a/media/video/capture/linux/video_capture_device_chromeos.cc b/media/video/capture/linux/video_capture_device_chromeos.cc
index abbc3b2c5444ca062d86809a354f759b947dedab..4a6b501f878eadb34120272b7ac6b00f95710cbc 100644
--- a/media/video/capture/linux/video_capture_device_chromeos.cc
+++ b/media/video/capture/linux/video_capture_device_chromeos.cc
@@ -41,14 +41,12 @@ class VideoCaptureDeviceChromeOS::ScreenObserverDelegate
  private:
   friend class base::RefCountedThreadSafe<ScreenObserverDelegate>;
 
-  virtual ~ScreenObserverDelegate() {
-    DCHECK(!capture_device_);
-  }
+  ~ScreenObserverDelegate() override { DCHECK(!capture_device_); }
 
-  virtual void OnDisplayAdded(const gfx::Display& /*new_display*/) override {}
-  virtual void OnDisplayRemoved(const gfx::Display& /*old_display*/) override {}
-  virtual void OnDisplayMetricsChanged(const gfx::Display& display,
-                                       uint32_t metrics) override {
+  void OnDisplayAdded(const gfx::Display& /*new_display*/) override {}
+  void OnDisplayRemoved(const gfx::Display& /*old_display*/) override {}
+  void OnDisplayMetricsChanged(const gfx::Display& display,
+                               uint32_t metrics) override {
     DCHECK(ui_task_runner_->BelongsToCurrentThread());
     if (!(metrics & DISPLAY_METRIC_ROTATION))
       return;