Convert animation and renderer code to know about BorderImageLength

Source/core/rendering/style/BorderImageLength.h

 /*
  * Copyright (c) 2013, Opera Software ASA. 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 45 matching lines @@
     }
 
     bool isNumber() const { return m_length.isRelative(); }
     bool isLength() const { return !isNumber(); }
 
     const Length& length() const { ASSERT(isLength()); return m_length; }
     Length& length() { ASSERT(isLength()); return m_length; }
 
     double number() const { ASSERT(isNumber()); return m_length.value(); }
 
-    // FIXME: Remove when the conversion to LengthOrMultipleOfBorderWidthBox is complete.
-    Length deprecatedUnifiedLength() const { return m_length; }
-
     bool operator==(const BorderImageLength& other) const
     {
         return m_length == other.m_length;
     }
 
     bool isZero() const
     {
         return m_length.isZero();
     }
 
 private:
     Length m_length;
 };
 
 } // namespace WebCore
 
 #endif // BorderImageLength_h