Standardize usage of virtual/override/final specifiers.

media/cast/receiver/frame_receiver_unittest.cc

Index: media/cast/receiver/frame_receiver_unittest.cc
diff --git a/media/cast/receiver/frame_receiver_unittest.cc b/media/cast/receiver/frame_receiver_unittest.cc
index abdfb9d14388b39bb9ec39a18df6b116a6102cf5..24e1a0b9eebe93f13cb41d69e47a37edeea88ab5 100644
--- a/media/cast/receiver/frame_receiver_unittest.cc
+++ b/media/cast/receiver/frame_receiver_unittest.cc
@@ -77,9 +77,9 @@ class FrameReceiverTest : public ::testing::Test {
                             task_runner_);
   }
 
-  virtual ~FrameReceiverTest() {}
+  ~FrameReceiverTest() override {}
 
-  virtual void SetUp() {
+  void SetUp() override {
     payload_.assign(kPacketSize, 0);
 
     // Always start with a key frame.