Dispel the myth that enclosingLayer can return zero

Source/web/WebViewImpl.cpp

 /*
  * Copyright (C) 2011, 2012 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 1165 matching lines @@
     // Always clear any existing highlight when this is invoked, even if we
     // don't get a new target to highlight.
     m_linkHighlights.clear();
 
     // LinkHighlight reads out layout and compositing state, so we need to make sure that's all up to date.
     layout();
 
     for (size_t i = 0; i < highlightNodes.size(); ++i) {
         Node* node = highlightNodes[i];
 
-        if (!node || !node->renderer() || !node->renderer()->enclosingLayer())
+        if (!node || !node->renderer())
             continue;
 
         Color highlightColor = node->renderer()->style()->tapHighlightColor();
         // Safari documentation for -webkit-tap-highlight-color says if the specified color has 0 alpha,
         // then tap highlighting is disabled.
         // http://developer.apple.com/library/safari/#documentation/appleapplications/reference/safaricssref/articles/standardcssproperties.html
         if (!highlightColor.alpha())
             continue;
 
         m_linkHighlights.append(LinkHighlight::create(node, this));
@@ skipping 2806 matching lines @@
     const PageScaleConstraints& constraints = m_pageScaleConstraintsSet.pageDefinedConstraints();
 
     if (!mainFrameImpl() || !mainFrameImpl()->frameView())
         return false;
 
     return mainFrameImpl()->frameView()->layoutSize().width() == m_size.width
         || (constraints.minimumScale == constraints.maximumScale && constraints.minimumScale != -1);
 }
 
 } // namespace blink