Convert GrClip to an abstract base class

src/core/SkImageFilter.cpp

Index: src/core/SkImageFilter.cpp
diff --git a/src/core/SkImageFilter.cpp b/src/core/SkImageFilter.cpp
index 899083dbb468260a3b63d04b6e5354971f84f34c..c7a570121b9a4d96f99244c1f7afa417f8f5cd1d 100644
--- a/src/core/SkImageFilter.cpp
+++ b/src/core/SkImageFilter.cpp
@@ -287,13 +287,13 @@ sk_sp<SkSpecialImage> SkImageFilter::DrawWithFP(GrContext* context,
         return nullptr;
     }
 
+    SkIRect dstIRect = SkIRect::MakeWH(bounds.width(), bounds.height());
     SkRect srcRect = SkRect::Make(bounds);
     SkRect dstRect = SkRect::MakeWH(srcRect.width(), srcRect.height());
-    GrClip clip(dstRect);
+    GrFixedClip clip(dstIRect);
     drawContext->fillRectToRect(clip, paint, SkMatrix::I(), dstRect, srcRect);
 
-    return SkSpecialImage::MakeFromGpu(SkIRect::MakeWH(bounds.width(), bounds.height()),
-                                       kNeedNewImageUniqueID_SpecialImage,
+    return SkSpecialImage::MakeFromGpu(dstIRect, kNeedNewImageUniqueID_SpecialImage,
                                        drawContext->asTexture());
 }
 #endif