Standardize usage of virtual/override/final specifiers.

media/cast/sender/video_sender_unittest.cc

Index: media/cast/sender/video_sender_unittest.cc
diff --git a/media/cast/sender/video_sender_unittest.cc b/media/cast/sender/video_sender_unittest.cc
index 2276e332b0a4511572404db97a47a5ee4a717df1..120d8c7678b624c30f2317f327607fc66617b083 100644
--- a/media/cast/sender/video_sender_unittest.cc
+++ b/media/cast/sender/video_sender_unittest.cc
@@ -155,9 +155,9 @@ class VideoSenderTest : public ::testing::Test {
         &transport_));
   }
 
-  virtual ~VideoSenderTest() {}
+  ~VideoSenderTest() override {}
 
-  virtual void TearDown() override {
+  void TearDown() override {
     video_sender_.reset();
     task_runner_->RunTasks();
   }