Add a map homogenous points to SkMatrix

include/core/SkMatrix.h

Index: include/core/SkMatrix.h
diff --git a/include/core/SkMatrix.h b/include/core/SkMatrix.h
index f148e390b5cd4930f2d985f61a286cda3748b7cc..432670eae3c5d6f5ce6d9b4d9e94b72bc820daa1 100644
--- a/include/core/SkMatrix.h
+++ b/include/core/SkMatrix.h
@@ -423,6 +423,19 @@ public:
         }
     }
 
+    /** Apply this matrix to the array of homogenous points, specified by src,
+        where a homogenous point is defined by 3 contiguous scalar values,
+        and write the transformed points into the array of scalars specified by dst.
+        dst[] = M * src[]
+        @param dst  Where the transformed coordinates are written. It must
+                    contain at least 3 * count entries
+        @param src  The original coordinates that are to be transformed. It
+                    must contain at least 3 * count entries
+        @param count The number of points in src to read, and then transform
+                     into dst.
+    */
+    void mapHomogenousPoints(SkScalar dst[], const SkScalar src[], int count) const;
+
     void mapXY(SkScalar x, SkScalar y, SkPoint* result) const {
         SkASSERT(result);
         this->getMapXYProc()(*this, x, y, result);
@@ -666,6 +679,8 @@ private:
                              int count);
     static void Persp_pts(const SkMatrix&, SkPoint dst[], const SkPoint[], int);
 
+    static void Homogenous_pts(const SkMatrix&, SkScalar dst[], const SkScalar[], int);
+
     static const MapPtsProc gMapPtsProcs[];
 
     friend class SkPerspIter;