Make SkImageFilter crop rects relative to the primitive origin, instead of relative to their parent

src/effects/SkMergeImageFilter.cpp

 /*
  * Copyright 2012 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkMergeImageFilter.h"
 #include "SkCanvas.h"
 #include "SkDevice.h"
@@ skipping 80 matching lines @@
     }
 
     // don't modify dst until now, so we don't accidentally change it in the
     // loop, but then return false on the next filter.
     *dst = totalBounds;
     return true;
 }
 
 bool SkMergeImageFilter::onFilterImage(Proxy* proxy, const SkBitmap& src,
                                        const SkMatrix& ctm,
-                                       SkBitmap* result, SkIPoint* loc) {
+                                       SkBitmap* result, SkIPoint* offset) {
     if (countInputs() < 1) {
         return false;
     }
 
     SkIRect bounds;
     src.getBounds(&bounds);
     if (!this->applyCropRect(&bounds, ctm)) {
         return false;
     }
 
@@ skipping 23 matching lines @@
         }
 
         if (fModes) {
             paint.setXfermodeMode((SkXfermode::Mode)fModes[i]);
         } else {
             paint.setXfermode(NULL);
         }
         canvas.drawSprite(*srcPtr, pos.x() - x0, pos.y() - y0, &paint);
     }
 
-    loc->fX += bounds.left();
-    loc->fY += bounds.top();
+    offset->fX = bounds.left();
+    offset->fY = bounds.top();
     *result = dst->accessBitmap(false);
     return true;
 }
 
 void SkMergeImageFilter::flatten(SkFlattenableWriteBuffer& buffer) const {
     this->INHERITED::flatten(buffer);
 
     buffer.writeBool(fModes != NULL);
     if (fModes) {
         buffer.writeByteArray(fModes, countInputs() * sizeof(fModes[0]));
@@ skipping 11 matching lines @@
         if (buffer.validate(buffer.getArrayCount() == size) &&
             buffer.readByteArray(fModes, size)) {
             for (int i = 0; i < nbInputs; ++i) {
                 buffer.validate(SkIsValidMode((SkXfermode::Mode)fModes[i]));
             }
         }
     } else {
         fModes = 0;
     }
 }