[CSS Grid Layout] Don't resolve align-self and justify-self properties

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 644696facbe1bee7c8cbc791e9ad8c2f4bb10ed7..69211a6d5697073f00928db42083ff57d152e4d7 100644
--- a/Source/core/rendering/RenderFlexibleBox.cpp
+++ b/Source/core/rendering/RenderFlexibleBox.cpp
@@ -196,7 +196,7 @@ static ItemPosition resolveAlignment(const RenderStyle* parentStyle, const Rende
 {
     ItemPosition align = childStyle->alignSelf();
     if (align == ItemPositionAuto)
-        align = (parentStyle->alignItems() == ItemPositionAuto) ? ItemPositionStretch : parentStyle->alignItems();
+        align = (parentStyle->alignItems() == ItemPositionAuto) ? ItemPositionStretch: parentStyle->alignItems();
     return align;
 }
 
@@ -1320,7 +1320,9 @@ void RenderFlexibleBox::alignChildren(const Vector<LineContext>& lineContexts)
             case ItemPositionLeft:
             case ItemPositionRight:
                 // FIXME: File a bug about implementing that. The extended grammar
-                // is not enabled by default so we shouldn't hit this codepath.
+                // is not implemented yet so we default to "stretch" for now.
+                break;
+            default:
                 ASSERT_NOT_REACHED();
                 break;
             }