Remove additionalOutlineSize in ShadowList: it is always 0.

Source/core/rendering/style/ShadowList.h

 /*
  * 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:
  *
  *     * 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 42 matching lines @@
     static PassRefPtr<ShadowList> adopt(ShadowDataVector& shadows)
     {
         return adoptRef(new ShadowList(shadows));
     }
     const ShadowDataVector& shadows() const { return m_shadows; }
     bool operator==(const ShadowList& o) const { return m_shadows == o.m_shadows; }
     bool operator!=(const ShadowList& o) const { return !(*this == o); }
 
     static PassRefPtr<ShadowList> blend(const ShadowList* from, const ShadowList* to, double progress);
 
-    void adjustRectForShadow(LayoutRect&, float additionalOutlineSize = 0) const;
-    void adjustRectForShadow(FloatRect&, float additionalOutlineSize = 0) const;
+    void adjustRectForShadow(LayoutRect&) const;
+    void adjustRectForShadow(FloatRect&) const;
 
     PassOwnPtr<DrawLooperBuilder> createDrawLooper(DrawLooperBuilder::ShadowAlphaMode, bool isHorizontal = true) const;
 
 private:
     ShadowList(ShadowDataVector& shadows)
     {
         // If we have no shadows, we use a null ShadowList
         ASSERT(!shadows.isEmpty());
         m_shadows.swap(shadows);
         m_shadows.shrinkToFit();
     }
     ShadowDataVector m_shadows;
 };
 
 } // namespace blink
 
 #endif // ShadowList_h