Make LayoutState always be RAII

Source/core/rendering/RenderGrid.cpp

 /*
  * Copyright (C) 2011 Apple 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 264 matching lines @@
     updateLogicalHeight();
 
     if (size() != previousSize)
         relayoutChildren = true;
 
     layoutPositionedObjects(relayoutChildren || isRoot());
 
     computeRegionRangeForBlock(flowThread);
 
     computeOverflow(oldClientAfterEdge);
-    statePusher.pop();
 
     updateLayerTransform();
 
     // Update our scroll information if we're overflow:auto/scroll/hidden now that we know if
     // we overflow or not.
     if (hasOverflowClip())
         layer()->scrollableArea()->updateAfterLayout();
 
     repainter.repaintAfterLayout();
 
@@ skipping 1086 matching lines @@
     if (isOutOfFlowPositioned())
         return "RenderGrid (positioned)";
     if (isAnonymous())
         return "RenderGrid (generated)";
     if (isRelPositioned())
         return "RenderGrid (relative positioned)";
     return "RenderGrid";
 }
 
 } // namespace WebCore