Add sk_ref_sp helper function.

include/core/SkRefCnt.h

Index: include/core/SkRefCnt.h
diff --git a/include/core/SkRefCnt.h b/include/core/SkRefCnt.h
index c3f724fa8ded11926e8f94e16d9e6e8e174d8cae..f159e3b1b705cb70aa63bb540d448241701c0c06 100644
--- a/include/core/SkRefCnt.h
+++ b/include/core/SkRefCnt.h
@@ -14,6 +14,8 @@
 #include <functional>
 #include <utility>
 
+#define SK_SUPPORT_TRANSITION_TO_SP_INTERFACES
+
 /** \class SkRefCntBase
 
     SkRefCntBase is the base class for objects that may be shared by multiple
@@ -430,4 +432,20 @@ sk_sp<T> sk_make_sp(Args&&... args) {
     return sk_sp<T>(new T(std::forward<Args>(args)...));
 }
 
+#ifdef SK_SUPPORT_TRANSITION_TO_SP_INTERFACES
+
+/*
+ *  Returns a sk_sp wrapping the provided ptr AND calls ref on it (if not null).
+ *
+ *  This is different than the semantics of the constructor for sk_sp, which just wraps the ptr,
+ *  effectively "adopting" it.
+ *
+ *  This function may be helpful while we convert callers from ptr-based to sk_sp-based parameters.
+ */
+template <typename T> sk_sp<T> sk_ref_sp(T* obj) {
+    return sk_sp<T>(SkSafeRef(obj));
+}
+
+#endif
+
 #endif