Make LayoutState always be RAII

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 696ff78943af6b463e13a24247c719476fbbc45f..686366aca2b905ea2c6e1ce314dbc963456655b6 100644
--- a/Source/core/rendering/RenderFlexibleBox.cpp
+++ b/Source/core/rendering/RenderFlexibleBox.cpp
@@ -241,8 +241,6 @@ void RenderFlexibleBox::layoutBlock(bool relayoutChildren)
     LayoutUnit previousHeight = logicalHeight();
     setLogicalHeight(borderAndPaddingLogicalHeight() + scrollbarLogicalHeight());
 
-    LayoutStateMaintainer statePusher(*this, locationOffset());
-
     RenderFlowThread* flowThread = flowThreadContainingBlock();
     if (updateRegionsAndShapesLogicalSize(flowThread))
         relayoutChildren = true;
@@ -256,11 +254,7 @@ void RenderFlexibleBox::layoutBlock(bool relayoutChildren)
     ChildFrameRects oldChildRects;
     appendChildFrameRects(oldChildRects);
 
-    Vector<LineContext> lineContexts;
-    layoutFlexItems(relayoutChildren, lineContexts);
-
-    updateLogicalHeight();
-    repositionLogicalHeightDependentFlexItems(lineContexts);
+    layoutFlexItems(relayoutChildren);
 
     RenderBlock::finishDelayUpdateScrollInfo();
 
@@ -274,7 +268,6 @@ void RenderFlexibleBox::layoutBlock(bool relayoutChildren)
     repaintChildrenDuringLayoutIfMoved(oldChildRects);
     // FIXME: css3/flexbox/repaint-rtl-column.html seems to repaint more overflow than it needs to.
     computeOverflow(clientLogicalBottomAfterRepositioning());
-    statePusher.pop();
 
     updateLayerTransform();
 
@@ -670,8 +663,10 @@ LayoutUnit RenderFlexibleBox::preferredMainAxisContentExtentForChild(RenderBox*
     return std::max(LayoutUnit(0), computeMainAxisExtentForChild(child, MainOrPreferredSize, flexBasis));
 }
 
-void RenderFlexibleBox::layoutFlexItems(bool relayoutChildren, Vector<LineContext>& lineContexts)
+void RenderFlexibleBox::layoutFlexItems(bool relayoutChildren)
 {
+    LayoutStateMaintainer statePusher(*this, locationOffset());
+    Vector<LineContext> lineContexts;
     OrderedFlexItemList orderedChildren;
     LayoutUnit sumFlexBaseSize;
     double totalFlexGrow;
@@ -707,6 +702,9 @@ void RenderFlexibleBox::layoutFlexItems(bool relayoutChildren, Vector<LineContex
         if (height() < minHeight)
             setLogicalHeight(minHeight);
     }
+
+    updateLogicalHeight();
+    repositionLogicalHeightDependentFlexItems(lineContexts);
 }
 
 LayoutUnit RenderFlexibleBox::autoMarginOffsetInMainAxis(const OrderedFlexItemList& children, LayoutUnit& availableFreeSpace)