Provide approximate type functions for SkMatrix44.

ui/gfx/transform.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_TRANSFORM_H_
 #define UI_GFX_TRANSFORM_H_
 
 #include <string>
 
 #include "base/compiler_specific.h"
@@ skipping 102 matching lines @@
   void ConcatTransform(const Transform& transform);
 
   // Returns true if this is the identity matrix.
   bool IsIdentity() const { return matrix_.isIdentity(); }
 
   // Returns true if the matrix is either identity or pure translation.
   bool IsIdentityOrTranslation() const {
     return !(matrix_.getType() & ~SkMatrix44::kTranslate_Mask);
   }
 
+  // Returns true if the matrix is either identity or pure translation,
+  // allowing for an amount of inaccuracy as specified by the parameter.
+  bool IsApproximatelyIdentityOrTranslation(SkMScalar tolerance) const;
+
   // Returns true if the matrix is either a positive scale and/or a translation.
   bool IsPositiveScaleOrTranslation() const {
     if (!IsScaleOrTranslation())
       return false;
     return matrix_.get(0, 0) > 0.0 && matrix_.get(1, 1) > 0.0 &&
            matrix_.get(2, 2) > 0.0;
   }
 
   // Returns true if the matrix is either identity or pure, non-fractional
   // translation.
@@ skipping 120 matching lines @@
                               Point3F* point) const;
 
   SkMatrix44 matrix_;
 
   // copy/assign are allowed.
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_TRANSFORM_H_