Fix virtual/override/final usage in Source/core/layout/.

Source/core/layout/LayoutPartTest.cpp

 // 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 "config.h"
 #include "core/layout/LayoutPart.h"
 
 #include "core/html/HTMLElement.h"
 #include "core/layout/ImageQualityController.h"
 #include "core/layout/LayoutTestHelper.h"
 #include <gtest/gtest.h>
 
 namespace blink {
 
 class LayoutPartTest : public RenderingTest {
 };
 
 class OverriddenLayoutPart : public LayoutPart {
 public:
     explicit OverriddenLayoutPart(Element* element) : LayoutPart(element) { }
 
-    virtual const char* name() const override { return "OverriddenLayoutPart"; }
+    const char* name() const override { return "OverriddenLayoutPart"; }
 };
 
 TEST_F(LayoutPartTest, DestroyUpdatesImageQualityController)
 {
     RefPtrWillBeRawPtr<Element> element = HTMLElement::create(HTMLNames::divTag, document());
     LayoutObject* part = new OverriddenLayoutPart(element.get());
     // The third and forth arguments are not important in this test.
     ImageQualityController::imageQualityController()->set(part, 0, this, LayoutSize(1, 1));
     EXPECT_TRUE(ImageQualityController::has(part));
     part->destroy();
     EXPECT_FALSE(ImageQualityController::has(part));
 }
 
 }