Remove unused TransformOperation::isIdentity

Source/platform/transforms/MatrixTransformOperation.h

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2003, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
@@ skipping 32 matching lines @@
     }
 
     TransformationMatrix matrix() const { return TransformationMatrix(m_a, m_b, m_c, m_d, m_e, m_f); }
 
     virtual bool canBlendWith(const TransformOperation& other) const
     {
         return false;
     }
 
 private:
-    virtual bool isIdentity() const OVERRIDE { return m_a == 1 && !m_b && !m_c && m_d == 1 && !m_e && !m_f; }
-
     virtual OperationType type() const OVERRIDE { return Matrix; }
 
     virtual bool operator==(const TransformOperation& o) const OVERRIDE
     {
         if (!isSameType(o))
             return false;
 
         const MatrixTransformOperation* m = static_cast<const MatrixTransformOperation*>(&o);
         return m_a == m->m_a && m_b == m->m_b && m_c == m->m_c && m_d == m->m_d && m_e == m->m_e && m_f == m->m_f;
     }
@@ skipping 30 matching lines @@
     double m_b;
     double m_c;
     double m_d;
     double m_e;
     double m_f;
 };
 
 } // namespace blink
 
 #endif // MatrixTransformOperation_h