no virtual destructor for point/size/rect

ui/gfx/rect_base.h

 // Copyright (c) 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.
 
 // A template for a simple rectangle class.  The containment semantics
 // are array-like; that is, the coordinate (x, y) is considered to be
 // contained by the rectangle, but the coordinate (x + width, y) is not.
 // The class will happily let you create malformed rectangles (that is,
 // rectangles with negative width and/or height), but there will be assertions
 // in the operations (such as Contains()) to complain in this case.
@@ skipping 122 matching lines @@
   void SplitVertically(Class* left_half, Class* right_half) const;
 
   // Returns true if this rectangle shares an entire edge (i.e., same width or
   // same height) with the given rectangle, and the rectangles do not overlap.
   bool SharesEdgeWith(const Class& rect) const;
 
  protected:
   RectBase(const PointClass& origin, const SizeClass& size);
   explicit RectBase(const SizeClass& size);
   explicit RectBase(const PointClass& origin);
-  virtual ~RectBase();
+  // Destructor is intentionally made non virtual and protected.
+  // Do not make this public.
+  ~RectBase();
 
  private:
   PointClass origin_;
   SizeClass size_;
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_RECT_BASE_H_