Make RenderObject::style() return a const object

Source/core/editing/SimplifyMarkupCommand.cpp

 /*
  * Copyright (C) 2012 Apple Computer, 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 37 matching lines @@
     // without affecting the style. The goal is to produce leaner markup even when starting
     // from a verbose fragment.
     // We look at inline elements as well as non top level divs that don't have attributes.
     for (Node* node = m_firstNode.get(); node && node != m_nodeAfterLast; node = NodeTraversal::next(*node)) {
         if (node->hasChildren() || (node->isTextNode() && node->nextSibling()))
             continue;
 
         ContainerNode* startingNode = node->parentNode();
         if (!startingNode)
             continue;
-        LayoutStyle* startingStyle = startingNode->layoutStyle();
+        const LayoutStyle* startingStyle = startingNode->layoutStyle();
         if (!startingStyle)
             continue;
         ContainerNode* currentNode = startingNode;
         ContainerNode* topNodeWithStartingStyle = nullptr;
         while (currentNode != rootNode) {
             if (currentNode->parentNode() != rootNode && isRemovableBlock(currentNode))
                 nodesToRemove.append(currentNode);
 
             currentNode = currentNode->parentNode();
             if (!currentNode)
@@ skipping 53 matching lines @@
 }
 
 void SimplifyMarkupCommand::trace(Visitor* visitor)
 {
     visitor->trace(m_firstNode);
     visitor->trace(m_nodeAfterLast);
     CompositeEditCommand::trace(visitor);
 }
 
 } // namespace blink