Revert last week's OrderIterator changes

Source/core/rendering/RenderFlexibleBox.cpp

Index: Source/core/rendering/RenderFlexibleBox.cpp
diff --git a/Source/core/rendering/RenderFlexibleBox.cpp b/Source/core/rendering/RenderFlexibleBox.cpp
index 62f6d971e3a6fc4b9c6b4ed35dfac471d7e7c5dd..d1c9cfc192bfbb9eb0cfdfc63080be7e27ef337a 100644
--- a/Source/core/rendering/RenderFlexibleBox.cpp
+++ b/Source/core/rendering/RenderFlexibleBox.cpp
@@ -265,13 +265,6 @@ void RenderFlexibleBox::styleDidChange(StyleDifference diff, const RenderStyle*
     }
 }
 
-void RenderFlexibleBox::removeChild(RenderObject* child)
-{
-    m_orderIterator.invalidate();
-
-    RenderBlock::removeChild(child);
-}
-
 void RenderFlexibleBox::layoutBlock(bool relayoutChildren, LayoutUnit)
 {
     ASSERT(needsLayout());