Create special surfaces according to original device (not always in N32)

src/effects/SkOffsetImageFilter.cpp

Index: src/effects/SkOffsetImageFilter.cpp
diff --git a/src/effects/SkOffsetImageFilter.cpp b/src/effects/SkOffsetImageFilter.cpp
index af60164d99040c3170c13b4a6820deb978ae2b8f..5730f1f80ea7f7ba116f6c26341b505b23b070a9 100644
--- a/src/effects/SkOffsetImageFilter.cpp
+++ b/src/effects/SkOffsetImageFilter.cpp
@@ -49,9 +49,7 @@ sk_sp<SkSpecialImage> SkOffsetImageFilter::onFilterImage(SkSpecialImage* source,
             return nullptr;
         }
 
-        SkImageInfo info = SkImageInfo::MakeN32(bounds.width(), bounds.height(),
-                                                kPremul_SkAlphaType);
-        sk_sp<SkSpecialSurface> surf(source->makeSurface(info));
+        sk_sp<SkSpecialSurface> surf(source->makeSurface(bounds));
         if (!surf) {
             return nullptr;
         }