[CSS Grid Layout] Remove stack from grid-auto-flow syntax

Source/core/rendering/style/RenderStyleConstants.h

Index: Source/core/rendering/style/RenderStyleConstants.h
diff --git a/Source/core/rendering/style/RenderStyleConstants.h b/Source/core/rendering/style/RenderStyleConstants.h
index 81e52cf2b667074151abc3dc7bb5162a060a08d5..a18075c683572759c2d97efe61cd11527b71ee32 100644
--- a/Source/core/rendering/style/RenderStyleConstants.h
+++ b/Source/core/rendering/style/RenderStyleConstants.h
@@ -467,25 +467,22 @@ enum WrapThrough { WrapThroughWrap, WrapThroughNone };
 
 enum RubyPosition { RubyPositionBefore, RubyPositionAfter };
 
-static const size_t GridAutoFlowBits = 5;
+static const size_t GridAutoFlowBits = 4;
 enum InternalGridAutoFlowAlgorithm {
     InternalAutoFlowAlgorithmSparse = 0x1,
-    InternalAutoFlowAlgorithmDense = 0x2,
-    InternalAutoFlowAlgorithmStack = 0x4
+    InternalAutoFlowAlgorithmDense = 0x2
 };
 
 enum InternalGridAutoFlowDirection {
-    InternalAutoFlowDirectionRow = 0x8,
-    InternalAutoFlowDirectionColumn = 0x10
+    InternalAutoFlowDirectionRow = 0x4,
+    InternalAutoFlowDirectionColumn = 0x8
 };
 
 enum GridAutoFlow {
     AutoFlowRow = InternalAutoFlowAlgorithmSparse | InternalAutoFlowDirectionRow,
     AutoFlowColumn = InternalAutoFlowAlgorithmSparse | InternalAutoFlowDirectionColumn,
     AutoFlowRowDense = InternalAutoFlowAlgorithmDense | InternalAutoFlowDirectionRow,
-    AutoFlowColumnDense = InternalAutoFlowAlgorithmDense | InternalAutoFlowDirectionColumn,
-    AutoFlowStackRow = InternalAutoFlowAlgorithmStack | InternalAutoFlowDirectionRow,
-    AutoFlowStackColumn = InternalAutoFlowAlgorithmStack | InternalAutoFlowDirectionColumn
+    AutoFlowColumnDense = InternalAutoFlowAlgorithmDense | InternalAutoFlowDirectionColumn
 };
 
 enum DraggableRegionMode { DraggableRegionNone, DraggableRegionDrag, DraggableRegionNoDrag };