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 259b3875b3a5cbddabbf57c0a9e82a1a02925846..79ba164b3e82905d5cdbb63846fa2d9f5c4ef08b 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()];
 }
 
@@ -769,7 +767,6 @@ void RenderTableSection::layout()
         }
     }
 
-    statePusher.pop();
     clearNeedsLayout();
 }
 
@@ -1019,8 +1016,6 @@ void RenderTableSection::layoutRows()
     setLogicalHeight(m_rowPos[totalRows]);
 
     computeOverflowFromCells(totalRows, nEffCols);
-
-    statePusher.pop();
 }
 
 void RenderTableSection::computeOverflowFromCells()