formalize named picture versions

src/core/SkPaint.cpp

Index: src/core/SkPaint.cpp
diff --git a/src/core/SkPaint.cpp b/src/core/SkPaint.cpp
index 7ac2f076b1fafb7f62f2e4c43537e6a9b2de3f60..ef7e030639da92ef2d0b1b4533c9179f40931453 100644
--- a/src/core/SkPaint.cpp
+++ b/src/core/SkPaint.cpp
@@ -1,4 +1,3 @@
-
 /*
  * Copyright 2006 The Android Open Source Project
  *
@@ -2182,9 +2181,8 @@ void SkPaint::unflatten(SkReadBuffer& buffer) {
     this->setStrokeMiter(read_scalar(pod));
     this->setColor(*pod++);
 
-    const int picVer = buffer.pictureVersion();
     unsigned flatFlags = 0;
-    if (picVer > 0 && picVer <= 22) {
+    if (buffer.pictureVersionLT(SkReadBuffer::kFilterLevelIsEnum_PictureVersion)) {
         flatFlags = unpack_paint_flags_v22(this, *pod++);
     } else {
         flatFlags = unpack_paint_flags(this, *pod++);