Require SK_DECLARE_STATIC_LAZY_PTR is used in global scope.

include/core/SkData.h

Index: include/core/SkData.h
diff --git a/include/core/SkData.h b/include/core/SkData.h
index e25ef50d711fcbfd0a262c122d1f8b53d1ca11b8..4f0c213da9bc6f07c9e89f87f77831fb66e763f4 100644
--- a/include/core/SkData.h
+++ b/include/core/SkData.h
@@ -171,8 +171,7 @@ private:
     virtual void internal_dispose() const SK_OVERRIDE;
 
     // Called the first time someone calls NewEmpty to initialize the singleton.
-    static SkData* NewEmptyImpl();
-    static void DeleteEmpty(SkData*);
+    friend SkData* sk_new_empty_data();
 
     // shared internal factory
     static SkData* PrivateNewWithCopy(const void* srcOrNull, size_t length);