Update from https://crrev.com/304418

cc/trees/occlusion_tracker_unittest.cc

 // Copyright 2012 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 "cc/trees/occlusion_tracker.h"
 
 #include "cc/animation/layer_animation_controller.h"
 #include "cc/base/math_util.h"
 #include "cc/layers/layer.h"
 #include "cc/layers/layer_impl.h"
@@ skipping 156 matching lines @@
 
 template <typename Types> class OcclusionTrackerTest : public testing::Test {
  protected:
   explicit OcclusionTrackerTest(bool opaque_layers)
       : opaque_layers_(opaque_layers),
         client_(FakeLayerTreeHostClient::DIRECT_3D),
         host_(FakeLayerTreeHost::Create(&client_)) {}
 
   virtual void RunMyTest() = 0;
 
-  virtual void TearDown() { DestroyLayers(); }
+  void TearDown() override { DestroyLayers(); }
 
   typename Types::HostType* GetHost();
 
   typename Types::ContentLayerType* CreateRoot(const gfx::Transform& transform,
                                                const gfx::PointF& position,
                                                const gfx::Size& bounds) {
     typename Types::ContentLayerPtrType layer(
         Types::CreateContentLayer(GetHost()));
     typename Types::ContentLayerType* layer_ptr = layer.get();
     SetProperties(layer_ptr, transform, position, bounds);
@@ skipping 3113 matching lines @@
     EXPECT_EQ(gfx::Rect(),
               occlusion.UnoccludedSurfaceContentRect(
                   surface, gfx::Rect(80, 70, 50, 50)));
   }
 };
 
 ALL_OCCLUSIONTRACKER_TEST(OcclusionTrackerTestUnoccludedSurfaceQuery)
 
 }  // namespace
 }  // namespace cc