Standardize usage of virtual/override/final specifiers.

components/login/screens/screen_context_unittest.cc

 // Copyright (c) 2013 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 <algorithm>
 #include <vector>
 
 #include "base/memory/scoped_ptr.h"
 #include "components/login/screens/screen_context.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace login {
 
 class ScreenContextTest : public testing::Test {
  public:
   ScreenContextTest() {}
-  virtual ~ScreenContextTest() {}
+  ~ScreenContextTest() override {}
 
-  virtual void SetUp() { context_.reset(new ScreenContext()); }
+  void SetUp() override { context_.reset(new ScreenContext()); }
 
-  virtual void TearDown() {}
+  void TearDown() override {}
 
  protected:
   ScreenContext& context() { return *context_.get(); }
 
  private:
   scoped_ptr<ScreenContext> context_;
 };
 
 TEST_F(ScreenContextTest, Simple) {
   ASSERT_FALSE(context().HasChanges());
@@ skipping 113 matching lines @@
   ASSERT_EQ("key1", keys[1]);
   ASSERT_EQ("key2", keys[2]);
 
   ASSERT_FALSE(context().HasChanges());
   ASSERT_EQ("value0", context().GetString("key0"));
   ASSERT_EQ(1, context().GetInteger("key1"));
   ASSERT_TRUE(context().GetBoolean("key2"));
 }
 
 }  // namespace login