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

gm/offsetimagefilter.cpp

Index: gm/offsetimagefilter.cpp
diff --git a/gm/offsetimagefilter.cpp b/gm/offsetimagefilter.cpp
index 2d77bbd243c99035f9b1436c16b6a429d969f946..95f1a31fe590461112d746977d28a5f987eed462 100644
--- a/gm/offsetimagefilter.cpp
+++ b/gm/offsetimagefilter.cpp
@@ -70,9 +70,10 @@ protected:
     void drawClippedBitmap(SkCanvas* canvas, const SkBitmap& bitmap, const SkPaint& paint,
                            SkScalar x, SkScalar y) {
         canvas->save();
-        canvas->clipRect(SkRect::MakeXYWH(x, y,
+        canvas->translate(x, y);
+        canvas->clipRect(SkRect::MakeXYWH(0, 0,
             SkIntToScalar(bitmap.width()), SkIntToScalar(bitmap.height())));
-        canvas->drawBitmap(bitmap, x, y, &paint);
+        canvas->drawBitmap(bitmap, 0, 0, &paint);
         canvas->restore();
     }
 
@@ -88,8 +89,8 @@ protected:
         int x = 0, y = 0;
         for (size_t i = 0; i < 4; i++) {
             SkBitmap* bitmap = (i & 0x01) ? &fCheckerboard : &fBitmap;
-            SkIRect cropRect = SkIRect::MakeXYWH(x + i * 12,
-                                                 y + i * 8,
+            SkIRect cropRect = SkIRect::MakeXYWH(i * 12,
+                                                 i * 8,
                                                  bitmap->width() - i * 8,
                                                  bitmap->height() - i * 12);
             SkImageFilter::CropRect rect(SkRect::Make(cropRect));