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

src/effects/SkMergeImageFilter.cpp

Index: src/effects/SkMergeImageFilter.cpp
diff --git a/src/effects/SkMergeImageFilter.cpp b/src/effects/SkMergeImageFilter.cpp
index 528fe823ebf7cdb6a3800f6fee31e7a0d9d1e476..9c0fa92a2b2cc81c5110ff06a0211966bc0c94a2 100755
--- a/src/effects/SkMergeImageFilter.cpp
+++ b/src/effects/SkMergeImageFilter.cpp
@@ -98,7 +98,7 @@ bool SkMergeImageFilter::onFilterBounds(const SkIRect& src, const SkMatrix& ctm,
 
 bool SkMergeImageFilter::onFilterImage(Proxy* proxy, const SkBitmap& src,
                                        const SkMatrix& ctm,
-                                       SkBitmap* result, SkIPoint* loc) {
+                                       SkBitmap* result, SkIPoint* offset) {
     if (countInputs() < 1) {
         return false;
     }
@@ -142,8 +142,8 @@ bool SkMergeImageFilter::onFilterImage(Proxy* proxy, const SkBitmap& src,
         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;
 }