Add isScale2d() helper function to SkMatrix44.

include/utils/SkMatrix44.h

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkMatrix44_DEFINED
 #define SkMatrix44_DEFINED
 
@@ skipping 207 matching lines @@
         return !(this->getType() & ~kTranslate_Mask);
     }
 
     /**
      *  Return true if the matrix only contains scale or translate or is identity.
      */
     inline bool isScaleTranslate() const {
         return !(this->getType() & ~(kScale_Mask | kTranslate_Mask));
     }
 
+    /**
+     *  Returns true if the matrix only contains scale or is identity.
+     */
+    inline bool isScale() const {
+            return !(this->getType() & ~kScale_Mask);
+    }
+
     inline bool hasPerspective() const {
         return SkToBool(this->getType() & kPerspective_Mask);
     }
 
     void setIdentity();
     inline void reset() { this->setIdentity();}
 
     /**
      *  get a value from the matrix. The row,col parameters work as follows:
      *  (0, 0)  scale-x
@@ skipping 218 matching lines @@
     /**
      *  Does not take the time to 'compute' the typemask. Only returns true if
      *  we already know that this matrix is identity.
      */
     inline bool isTriviallyIdentity() const {
         return 0 == fTypeMask;
     }
 };
 
 #endif