change readTypeface to return sk_sp

src/core/SkPaint.cpp

Index: src/core/SkPaint.cpp
diff --git a/src/core/SkPaint.cpp b/src/core/SkPaint.cpp
index 44b2928c25bb7b4cbf1c318f5f7bfee898472946..58d6a0f95c94d05d1bade46c19815d3d3959a490 100644
--- a/src/core/SkPaint.cpp
+++ b/src/core/SkPaint.cpp
@@ -1958,7 +1958,7 @@ void SkPaint::unflatten(SkReadBuffer& buffer) {
     this->setTextEncoding(static_cast<TextEncoding>((tmp >> 0) & 0xFF));
 
     if (flatFlags & kHasTypeface_FlatFlag) {
-        this->setTypeface(sk_ref_sp(buffer.readTypeface()));
+        this->setTypeface(buffer.readTypeface());
     } else {
         this->setTypeface(nullptr);
     }