Set ComputedStyle on Node and use that in buildOwnLayout()

third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp

 /*
  * Copyright (C) 2004, 2006, 2007 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alp Toker <alp@atoker.com>
  * Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
@@ skipping 262 matching lines @@
         return canCreateImageBuffer(size());
     return buffer();
 }
 
 void HTMLCanvasElement::didDraw(const FloatRect& rect)
 {
     if (rect.isEmpty())
         return;
     m_imageBufferIsClear = false;
     clearCopiedImage();
-    if (layoutObject())
+    if (hasLayoutObject())
         layoutObject()->setMayNeedPaintInvalidation();
     if (m_context && m_context->is2d() && m_context->shouldAntialias() && page() && page()->deviceScaleFactor() > 1.0f) {
         FloatRect inflatedRect = rect;
         inflatedRect.inflate(1);
         m_dirtyRect.unite(inflatedRect);
     } else {
         m_dirtyRect.unite(rect);
     }
     if (m_context && m_context->is2d() && hasImageBuffer())
         buffer()->didDraw(rect);
@@ skipping 894 matching lines @@
 
 bool HTMLCanvasElement::createSurfaceLayer()
 {
     DCHECK(!m_surfaceLayerBridge);
     std::unique_ptr<CanvasSurfaceLayerBridgeClient> bridgeClient = wrapUnique(new CanvasSurfaceLayerBridgeClientImpl());
     m_surfaceLayerBridge = wrapUnique(new CanvasSurfaceLayerBridge(std::move(bridgeClient)));
     return m_surfaceLayerBridge->createSurfaceLayer(this->width(), this->height());
 }
 
 } // namespace blink