Functions that return non-const internal data should not be const because it provides a loophole ar…

ui/gfx/canvas.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.
 
 #ifndef UI_GFX_CANVAS_H_
 #define UI_GFX_CANVAS_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
@@ skipping 403 matching lines @@
   // Apply transformation on the canvas.
   void Transform(const Transform& transform);
 
   // Draws the given string with a fade gradient at the end.
   void DrawFadedString(const base::string16& text,
                        const FontList& font_list,
                        SkColor color,
                        const Rect& display_rect,
                        int flags);
 
-  skia::PlatformCanvas* platform_canvas() const { return owned_canvas_.get(); }
-  SkCanvas* sk_canvas() const { return canvas_; }
+  skia::PlatformCanvas* platform_canvas() { return owned_canvas_.get(); }
+  SkCanvas* sk_canvas() { return canvas_; }
   float image_scale() const { return image_scale_; }
 
  private:
   Canvas(SkCanvas* canvas, float image_scale);
 
   // Test whether the provided rectangle intersects the current clip rect.
   bool IntersectsClipRectInt(int x, int y, int w, int h);
   bool IntersectsClipRect(const Rect& rect);
 
   // Helper for the DrawImageInt functions declared above. The |pixel|
@@ skipping 20 matching lines @@
 
   skia::RefPtr<skia::PlatformCanvas> owned_canvas_;
   SkCanvas* canvas_;
 
   DISALLOW_COPY_AND_ASSIGN(Canvas);
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_CANVAS_H_