Add option to skip rects to drawImageLattice()

src/core/SkLatticeIter.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkLatticeIter_DEFINED
 #define SkLatticeIter_DEFINED
 
@@ skipping 23 matching lines @@
      *  While it returns true, use src/dst to draw the image/bitmap
      */
     bool next(SkRect* src, SkRect* dst);
 
     /**
      *  Apply a matrix to the dst points.
      */
     void mapDstScaleTranslate(const SkMatrix& matrix);
 
     /**
-     *  Returns the total number of rects that will be drawn.
+     *  Returns the number of rects that will actually be drawn.
      */
-    int numRects() const {
-        return fNumRects;
+    int numRectsToDraw() const {
+        return fNumRectsToDraw;
     }
 
 private:
     SkTArray<SkScalar> fSrcX;
     SkTArray<SkScalar> fSrcY;
     SkTArray<SkScalar> fDstX;
     SkTArray<SkScalar> fDstY;
+    SkTArray<SkCanvas::Lattice::Flags> fFlags;
 
     int  fCurrX;
     int  fCurrY;
-    bool fDone;
-    int  fNumRects;
+    int  fNumRectsInLattice;
+    int  fNumRectsToDraw;
 };
 
 #endif