formalize named picture versions

src/core/SkShader.cpp

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBitmapProcShader.h"
 #include "SkEmptyShader.h"
 #include "SkReadBuffer.h"
@@ skipping 237 matching lines @@
     : fColor(c) {
 }
 
 bool SkColorShader::isOpaque() const {
     return SkColorGetA(fColor) == 255;
 }
 
 SkColorShader::SkColorShader(SkReadBuffer& b) : INHERITED(b) {
     // V25_COMPATIBILITY_CODE We had a boolean to make the color shader inherit the paint's
     // color. We don't support that any more.
-    if (b.pictureVersion() < 26 && 0 != b.pictureVersion()) {
+    if (b.pictureVersionLT(SkReadBuffer::kColorShaderNoBool_PictureVersion)) {
         if (b.readBool()) {
             SkDEBUGFAIL("We shouldn't have pictures that recorded the inherited case.");
             fColor = SK_ColorWHITE;
             return;
         }
     }
     fColor = b.readColor();
 }
 
 void SkColorShader::flatten(SkWriteBuffer& buffer) const {
@@ skipping 91 matching lines @@
 #include "SkEmptyShader.h"
 
 void SkEmptyShader::toString(SkString* str) const {
     str->append("SkEmptyShader: (");
 
     this->INHERITED::toString(str);
 
     str->append(")");
 }
 #endif