Optimize hasTagName when called on an HTMLElement / SVGElement

Source/core/rendering/compositing/CompositedLayerMapping.cpp

 /*
  * Copyright (C) 2009, 2010, 2011 Apple Inc. 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.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 1678 matching lines @@
     if (renderObject->node() && renderObject->node()->isDocumentNode()) {
         // Look to see if the root object has a non-simple background
         RenderObject* rootObject = renderObject->document().documentElement() ? renderObject->document().documentElement()->renderer() : 0;
         // Reject anything that has a border, a border-radius or outline,
         // or is not a simple background (no background, or solid color).
         if (rootObject && hasBoxDecorationsOrBackgroundImage(rootObject->style()))
             return true;
 
         // Now look at the body's renderer.
         HTMLElement* body = renderObject->document().body();
-        RenderObject* bodyObject = (body && body->hasLocalName(bodyTag)) ? body->renderer() : 0;
+        RenderObject* bodyObject = isHTMLBodyElement(body) ? body->renderer() : 0;
         if (bodyObject && hasBoxDecorationsOrBackgroundImage(bodyObject->style()))
             return true;
     }
 
     // FIXME: it's O(n^2). A better solution is needed.
     return paintsChildren();
 }
 
 // An image can be directly compositing if it's the sole content of the layer, and has no box decorations
 // that require painting. Direct compositing saves backing store.
@@ skipping 540 matching lines @@
     } else if (graphicsLayer == m_scrollingBlockSelectionLayer.get()) {
         name = "Scrolling Block Selection Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
 } // namespace blink