Add a src rect to drawImageLattice() API

src/pdf/SkPDFCanvas.cpp

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkLatticeIter.h"
 #include "SkPDFCanvas.h"
 #include "SkPDFDevice.h"
@@ skipping 71 matching lines @@
     }
     this->concat(SkMatrix::MakeRectToRect(src, dst,
                                  SkMatrix::kFill_ScaleToFit));
     this->drawBitmap(bitmap, 0, 0, paint);
 }
 
 void SkPDFCanvas::onDrawImageLattice(const SkImage* image,
                                      const Lattice& lattice,
                                      const SkRect& dst,
                                      const SkPaint* paint) {
-    SkLatticeIter iter(image->width(), image->height(), lattice, dst);
+    SkLatticeIter iter(lattice, dst);
     SkRect srcR, dstR;
     while (iter.next(&srcR, &dstR)) {
         this->drawImageRect(image, srcR, dstR, paint);
     }
 }
 
 void SkPDFCanvas::onDrawBitmapLattice(const SkBitmap& bitmap,
                                       const Lattice& lattice,
                                       const SkRect& dst,
                                       const SkPaint* paint) {
-    SkLatticeIter iter(bitmap.width(), bitmap.height(), lattice, dst);
+    SkLatticeIter iter(lattice, dst);
     SkRect srcR, dstR;
     while (iter.next(&srcR, &dstR)) {
         this->drawBitmapRect(bitmap, srcR, dstR, paint);
     }
 }