[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..c113aec76e2fdac9f8e78a5aa56822095bd7118a 100644
--- a/Source/core/rendering/style/RenderStyleConstants.h
+++ b/Source/core/rendering/style/RenderStyleConstants.h
@@ -483,7 +483,7 @@ enum WrapThrough { WrapThroughWrap, WrapThroughNone };
 
 enum RubyPosition { RubyPositionBefore, RubyPositionAfter };
 
-enum GridAutoFlow { AutoFlowNone, AutoFlowColumn, AutoFlowRow };
+enum GridAutoFlow { AutoFlowRow, AutoFlowColumn, AutoFlowRowDense, AutoFlowColumnDense, AutoFlowStackRow, AutoFlowStackColumn };

[Julien - ping for review, 2014/06/27 17:44:53]

I wonder if we couldn't choose the value to make for easier comparisons.

You know that you have a base value which is either 'flow', 'dense' or 'stack'
suffixed by 'row' or 'column' so we could do:

enum InternalGridAutoFlowAlgorithm {
   InternalGridAutoFlowFlow = 0x1,
    InternalGridAutoFlowDense = 0x2,
    InternalGridAutoFlowStack = 0x4
};


enum InternalGridAutoFlowDirection {
    InternalGridAutoFlowColumn = 0x10,
    InternalGridAutoFlowRow = 0x20
};

enum GridAutoFlow {
    AutoFlowRow = InternalGridAutoFlowFlow | InternalGridAutoFlowRow,
    AutoFlowColumn = InternalGridAutoFlowFlow | InternalGridAutoFlowColumn,
    AutoFlowRowDense = InternalGridAutoFlowDense | InternalGridAutoFlowRow,
    [...]
};

(It's a bit too verbose for my taste but you get the idea)

With these you can easily know if something is 'dense' or flows along the 'row'
by some simple bitwise arithmetic. We can wrap these into helper function so
that we don't expose these details to RenderGrid.

[Manuel Rego, 2014/06/27 22:43:51]

Thanks for the suggestion. I've changed it and I've added some helper functions
in RenderStyle.

Now the code in RenderGrid that needs to know if you're in row or column
direction, or if the algorithm is stack or not is much simpler.

 
 enum DraggableRegionMode { DraggableRegionNone, DraggableRegionDrag, DraggableRegionNoDrag };