Fix const correctness of containerForRepaint

Source/core/rendering/RenderObject.h

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Google 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
@@ skipping 795 matching lines @@
         Color color;
         TextDecorationStyle style;
         AppliedTextDecoration() : color(Color::transparent), style(TextDecorationStyleSolid) { }
     };
 
     void getTextDecorations(unsigned decorations, AppliedTextDecoration& underline, AppliedTextDecoration& overline, AppliedTextDecoration& linethrough, bool quirksMode = false, bool firstlineStyle = false);
 
     // Return the RenderLayerModelObject in the container chain which is responsible for painting this object, or 0
     // if painting is root-relative. This is the container that should be passed to the 'forRepaint'
     // methods.
-    RenderLayerModelObject* containerForRepaint() const;
+    const RenderLayerModelObject* containerForRepaint() const;
 
     // Actually do the repaint of rect r for this object which has been computed in the coordinate space
     // of repaintContainer. If repaintContainer is 0, repaint via the view.
     void repaintUsingContainer(const RenderLayerModelObject* repaintContainer, const IntRect&, InvalidationReason) const;
 
     // Repaint the entire object.  Called when, e.g., the color of a border changes, or when a border
     // style changes.
     void repaint() const;
 
     // Repaint a specific subrectangle within a given object.  The rect |r| is in the object's coordinate space.
     void repaintRectangle(const LayoutRect&) const;
 
     // Repaint only if our old bounds and new bounds are different. The caller may pass in newBounds if they are known.
     bool repaintAfterLayoutIfNeeded(const RenderLayerModelObject* repaintContainer, bool wasSelfLayout,
-        const LayoutRect& oldBounds, const LayoutPoint& oldPositionFromRepaintContainer, const LayoutRect* newBoundsPtr = 0, const LayoutPoint* newPositionFromRepaintContainer = 0);
+        const LayoutRect& oldBounds, const LayoutPoint& oldPositionFromRepaintContainer, const LayoutRect* newBoundsPtr = 0, const LayoutPoint* newPositionFromRepaintContainer = 0) const;

[Julien - ping for review, 2014/05/07 22:55:42]

I am on the fence about that. While it is true that we don't modify RenderObject
in this function now, it doesn't mean that we won't in the future or that it's
wrong in the long run.

If that's not required by some of your 'const' change, I would just ignore that
part for now.

 
     // Walk the tree after layout repainting renderers that have changed or moved, updating bounds that have changed, and clearing repaint state.
     virtual void repaintTreeAfterLayout();
 
     virtual void repaintOverflow();
     void repaintOverflowIfNeeded();
 
     bool checkForRepaint() const;
     bool checkForRepaintDuringLayout() const;
 
@@ skipping 619 matching lines @@
 void showTree(const WebCore::RenderObject*);
 void showLineTree(const WebCore::RenderObject*);
 void showRenderTree(const WebCore::RenderObject* object1);
 // We don't make object2 an optional parameter so that showRenderTree
 // can be called from gdb easily.
 void showRenderTree(const WebCore::RenderObject* object1, const WebCore::RenderObject* object2);
 
 #endif
 
 #endif // RenderObject_h