Make RenderObject::style() return a const object

Source/core/layout/LayoutCounter.cpp

 /**
  * Copyright (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2006, 2007 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 93 matching lines @@
 static bool planCounter(RenderObject& object, const AtomicString& identifier, bool& isReset, int& value)
 {
     // Real text nodes don't have their own style so they can't have counters.
     // We can't even look at their styles or we'll see extra resets and increments!
     if (object.isText() && !object.isBR())
         return false;
     Node* generatingNode = object.generatingNode();
     // We must have a generating node or else we cannot have a counter.
     if (!generatingNode)
         return false;
-    RenderStyle* style = object.style();
+    const RenderStyle* style = object.style();
     ASSERT(style);
 
     switch (style->styleType()) {
     case NOPSEUDO:
         // Sometimes nodes have more then one renderer. Only the first one gets the counter
         // LayoutTests/http/tests/css/counter-crash.html
         if (generatingNode->renderer() != &object)
             return false;
         break;
     case BEFORE:
@@ skipping 484 matching lines @@
             fprintf(stderr, "    ");
         fprintf(stderr, "%p N:%p P:%p PS:%p NS:%p C:%p\n",
             current, current->node(), current->parent(), current->previousSibling(),
             current->nextSibling(), current->hasCounterNodeMap() ?
             counterName ? blink::counterMaps().get(current)->get(identifier) : (blink::CounterNode*)1 : (blink::CounterNode*)0);
     }
     fflush(stderr);
 }
 
 #endif // NDEBUG