Remove virtual destructors for several graphics classes

Source/core/platform/graphics/skia/OpaqueRegionSkia.cpp

 /*
  * Copyright (c) 2012, Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 27 matching lines @@
 #include "SkColorFilter.h"
 #include "SkShader.h"
 
 namespace WebCore {
 
 OpaqueRegionSkia::OpaqueRegionSkia()
     : m_opaqueRect(SkRect::MakeEmpty())
 {
 }
 
-OpaqueRegionSkia::~OpaqueRegionSkia()
-{
-}
-
 IntRect OpaqueRegionSkia::asRect() const
 {
     // Returns the largest enclosed rect.
     int left = SkScalarCeil(m_opaqueRect.fLeft);
     int top = SkScalarCeil(m_opaqueRect.fTop);
     int right = SkScalarFloor(m_opaqueRect.fRight);
     int bottom = SkScalarFloor(m_opaqueRect.fBottom);
     return IntRect(left, top, right-left, bottom-top);
 }
 
@@ skipping 366 matching lines @@
     opaqueRect.setEmpty();
 }
 
 SkRect& OpaqueRegionSkia::currentTrackingOpaqueRect()
 {
     // If we are drawing into a canvas layer, then track the opaque rect in that layer.
     return m_canvasLayerStack.isEmpty() ? m_opaqueRect : m_canvasLayerStack.last().opaqueRect;
 }
 
 } // namespace WebCore