[CSS Grid Layout] Update grid-auto-flow to the new 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 b0585fc78b564c2b64acc44670daea5b27c8eff2..e0142d11af77e0c60ba652d81a19798e5baf619a 100644
--- a/Source/core/rendering/style/RenderStyleConstants.h
+++ b/Source/core/rendering/style/RenderStyleConstants.h
@@ -483,7 +483,26 @@ enum WrapThrough { WrapThroughWrap, WrapThroughNone };
 
 enum RubyPosition { RubyPositionBefore, RubyPositionAfter };
 
-enum GridAutoFlow { AutoFlowNone, AutoFlowColumn, AutoFlowRow };
+static const size_t GridAutoFlowBits = 5;
+enum GridAutoFlowAlgorithm {
+    AutoFlowAlgorithmSparse = 0x1,
+    AutoFlowAlgorithmDense = 0x2,
+    AutoFlowAlgorithmStack = 0x4
+};
+
+enum GridAutoFlowDirection {

[Julien - ping for review, 2014/06/29 01:02:25]

I would put internal in the names to underline that they are not mapping to any
property.

+    AutoFlowDirectionRow = 0x8,
+    AutoFlowDirectionColumn = 0x10
+};
+
+enum GridAutoFlow {
+    AutoFlowRow = AutoFlowAlgorithmSparse | AutoFlowDirectionRow,
+    AutoFlowColumn = AutoFlowAlgorithmSparse | AutoFlowDirectionColumn,
+    AutoFlowRowDense = AutoFlowAlgorithmDense | AutoFlowDirectionRow,
+    AutoFlowColumnDense = AutoFlowAlgorithmDense | AutoFlowDirectionColumn,
+    AutoFlowStackRow = AutoFlowAlgorithmStack | AutoFlowDirectionRow,
+    AutoFlowStackColumn = AutoFlowAlgorithmStack | AutoFlowDirectionColumn
+};
 
 enum DraggableRegionMode { DraggableRegionNone, DraggableRegionDrag, DraggableRegionNoDrag };