Refactor CRC2D::reset() to avoid non-additive SkCanvas state operations

third_party/WebKit/Source/modules/csspaint/PaintRenderingContext2D.cpp

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "modules/csspaint/PaintRenderingContext2D.h"
 
 #include "platform/graphics/ImageBuffer.h"
 #include <memory>
 
 namespace blink {
@@ skipping 49 matching lines @@
   ASSERT(m_imageBuffer);
   return m_imageBuffer->baseTransform();
 }
 
 void PaintRenderingContext2D::didDraw(const SkIRect& dirtyRect) {
   ASSERT(m_imageBuffer);
   return m_imageBuffer->didDraw(SkRect::Make(dirtyRect));
 }
 
 void PaintRenderingContext2D::validateStateStack() const {
-#if ENABLE(ASSERT)
-  SkCanvas* skCanvas = existingDrawingCanvas();
-  if (skCanvas) {
-    ASSERT(static_cast<size_t>(skCanvas->getSaveCount()) ==
-           m_stateStack.size());
+#if DCHECK_IS_ON()
+  if (SkCanvas* skCanvas = existingDrawingCanvas()) {
+    DCHECK_EQ(static_cast<size_t>(skCanvas->getSaveCount()),
+              m_stateStack.size() + 1);
   }
 #endif
 }
 
 }  // namespace blink