factories should return baseclass, allowing the impl to specialize

src/effects/SkTileImageFilter.cpp

Index: src/effects/SkTileImageFilter.cpp
diff --git a/src/effects/SkTileImageFilter.cpp b/src/effects/SkTileImageFilter.cpp
index 5e633a355678c4997d9bf7df1b685c3fdc70f71e..c3eb2f301ac91d47652c1e4f107667b5b2afa371 100644
--- a/src/effects/SkTileImageFilter.cpp
+++ b/src/effects/SkTileImageFilter.cpp
@@ -16,8 +16,8 @@
 #include "SkShader.h"
 #include "SkValidationUtils.h"
 
-SkTileImageFilter* SkTileImageFilter::Create(const SkRect& srcRect, const SkRect& dstRect,
-                                             SkImageFilter* input) {
+SkImageFilter* SkTileImageFilter::Create(const SkRect& srcRect, const SkRect& dstRect,
+                                         SkImageFilter* input) {
     if (!SkIsValidRect(srcRect) || !SkIsValidRect(dstRect)) {
         return nullptr;
     }