Avoid layout when list color changes

Source/core/rendering/RenderListMarker.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Andrew Wellington (proton@wiretapped.net)
  * Copyright (C) 2010 Daniel Bates (dbates@intudata.com)
  *
  * 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
@@ skipping 1615 matching lines @@
 
     if (selectionState() == SelectionNone || !inlineBoxWrapper())
         return LayoutRect();
 
     RootInlineBox& root = inlineBoxWrapper()->root();
     LayoutRect rect(0, root.selectionTop() - y(), width(), root.selectionHeight());
     mapRectToPaintInvalidationBacking(paintInvalidationContainer, rect, 0);
     return rect;
 }
 
+void RenderListMarker::listItemStyleDidChange()
+{
+    RefPtr<RenderStyle> newStyle = RenderStyle::create();
+    // The marker always inherits from the list item, regardless of where it might end
+    // up (e.g., in some deeply nested line box). See CSS3 spec.
+    newStyle->inheritFrom(m_listItem->style());
+    if (style()) {
+        // Reuse the current margins otherwise resetting the margins to initial values

[mstensho (USE GERRIT), 2014/10/14 19:51:39]

Could you add something in front of "otherwise"? Either a semicolon or a full
stop, perhaps.

[Xianzhu, 2014/10/14 20:38:42]

Done.

+        // would trigger unnecessary layout.
+        newStyle->setMarginStart(style()->marginStart());
+        newStyle->setMarginEnd(style()->marginRight());
+    }
+    setStyle(newStyle.release());
+}
+
 } // namespace blink