Make LayoutState always be RAII

Source/core/rendering/RenderTableSection.cpp

Index: Source/core/rendering/RenderTableSection.cpp
diff --git a/Source/core/rendering/RenderTableSection.cpp b/Source/core/rendering/RenderTableSection.cpp
index 3429da4e010ed5f09baca9ce3a8e7392568fd5ad..e0c1f0d2f45cb955b1b4a20cda465b8bac361801 100644
--- a/Source/core/rendering/RenderTableSection.cpp
+++ b/Source/core/rendering/RenderTableSection.cpp
@@ -716,8 +716,6 @@ int RenderTableSection::calcRowLogicalHeight()
 
     ASSERT(!needsLayout());
 
-    statePusher.pop();
-
     return m_rowPos[m_grid.size()];
 }
 
@@ -766,7 +764,6 @@ void RenderTableSection::layout()
             rowRenderer->layoutIfNeeded();
     }
 
-    statePusher.pop();
     clearNeedsLayout();
 }
 
@@ -1016,8 +1013,6 @@ void RenderTableSection::layoutRows()
     setLogicalHeight(m_rowPos[totalRows]);
 
     computeOverflowFromCells(totalRows, nEffCols);
-
-    statePusher.pop();
 }
 
 void RenderTableSection::computeOverflowFromCells()