WebCore::Gradient need not have mutable fields.

Source/platform/graphics/Gradient.h

 /*
  * Copyright (C) 2006, 2007, 2008, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alp Toker <alp@atoker.com>
  * Copyright (C) 2008 Torch Mobile, Inc.
  * Copyright (C) 2013 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:
  * 1. Redistributions of source code must retain the above copyright
@@ skipping 123 matching lines @@
 
     void destroyShader();
 
     void sortStopsIfNecessary();
 
     FloatPoint m_p0;
     FloatPoint m_p1;
     float m_r0;
     float m_r1;
     float m_aspectRatio; // For elliptical gradient, width / height.
-    mutable Vector<ColorStop, 2> m_stops;
+    Vector<ColorStop, 2> m_stops;
     bool m_radial;
-    mutable bool m_stopsSorted;
+    bool m_stopsSorted;
     bool m_drawInPMColorSpace;
     GradientSpreadMethod m_spreadMethod;
     AffineTransform m_gradientSpaceTransformation;
 
-
     RefPtr<SkShader> m_gradient;
 };
 
 } // namespace WebCore
 
 #endif