Make RenderObject::style() return a const object

Source/core/dom/PseudoElement.cpp

 /*
  * Copyright (C) 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.
  *     * Neither the name of Google Inc. nor the names of its
@@ skipping 138 matching lines @@
         return;
 
     // The renderers inside pseudo elements are anonymous so they don't get notified of recalcStyle and must have
     // the style propagated downward manually similar to LayoutObject::propagateStyleToAnonymousChildren.
     LayoutObject* renderer = this->renderer();
     for (LayoutObject* child = renderer->nextInPreOrder(renderer); child; child = child->nextInPreOrder(renderer)) {
         // We only manage the style for the generated content items.
         if (!child->isText() && !child->isQuote() && !child->isImage())
             continue;
 
-        child->setPseudoStyle(renderer->style());
+        child->setPseudoStyle(renderer->mutableStyle());
     }
 }
 
 } // namespace