Standardize usage of virtual/override/final in cc/

cc/test/fake_picture_pile_impl.h

 // Copyright 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.
 
 #ifndef CC_TEST_FAKE_PICTURE_PILE_IMPL_H_
 #define CC_TEST_FAKE_PICTURE_PILE_IMPL_H_
 
 #include "base/memory/ref_counted.h"
 #include "cc/resources/picture_pile_impl.h"
 #include "cc/test/fake_content_layer_client.h"
@@ skipping 54 matching lines @@
   }
 
   void set_clear_canvas_with_debug_color(bool clear) {
     clear_canvas_with_debug_color_ = clear;
   }
 
   void set_has_text(bool has_text) { has_text_ = has_text; }
 
  protected:
   FakePicturePileImpl();
-  virtual ~FakePicturePileImpl();
+  ~FakePicturePileImpl() override;
 
   FakeContentLayerClient client_;
   SkPaint default_paint_;
 };
 
 }  // namespace cc
 
 #endif  // CC_TEST_FAKE_PICTURE_PILE_IMPL_H_