Standardize usage of virtual/override/final specifiers.

media/base/wall_clock_time_source_unittest.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/test/simple_test_tick_clock.h"
 #include "media/base/wall_clock_time_source.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace media {
 
 class WallClockTimeSourceTest : public testing::Test {
  public:
   WallClockTimeSourceTest() : tick_clock_(new base::SimpleTestTickClock()) {
     time_source_.SetTickClockForTesting(
         scoped_ptr<base::TickClock>(tick_clock_));
   }
-  virtual ~WallClockTimeSourceTest() {}
+  ~WallClockTimeSourceTest() override {}
 
   void AdvanceTimeInSeconds(int seconds) {
     tick_clock_->Advance(base::TimeDelta::FromSeconds(seconds));
   }
 
   int CurrentMediaTimeInSeconds() {
     return time_source_.CurrentMediaTime().InSeconds();
   }
 
   void SetMediaTimeInSeconds(int seconds) {
@@ skipping 53 matching lines @@
   AdvanceTimeInSeconds(10);
   EXPECT_EQ(10, CurrentMediaTimeInSeconds());
 
   time_source_.StopTicking();
 
   AdvanceTimeInSeconds(10);
   EXPECT_EQ(10, CurrentMediaTimeInSeconds());
 }
 
 }  // namespace media