[CSS Grid Layout] Implement 'justify-self' parsing

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 e1efd267f547ca405e3db12d02d7893ea1ee1875..b8ec6f13058d7fb8ae1744f2a4e70e929a52cf6e 100755
--- a/Source/core/rendering/style/RenderStyleConstants.h
+++ b/Source/core/rendering/style/RenderStyleConstants.h
@@ -531,6 +531,27 @@ enum EIsolation { IsolationAuto, IsolationIsolate };
 
 enum TouchActionDelay { TouchActionDelayNone, TouchActionDelayScript };
 
+enum JustifySelf {
+    JustifySelfAuto,
+    JustifySelfStretch,
+    JustifySelfBaseline,
+    JustifySelfCenter,
+    JustifySelfStart,
+    JustifySelfEnd,
+    JustifySelfSelfStart,
+    JustifySelfSelfEnd,
+    JustifySelfFlexStart,
+    JustifySelfFlexEnd,
+    JustifySelfLeft,
+    JustifySelfRight
+};
+
+enum JustifySelfOverflowAlignment {
+    JustifySelfOverflowAlignmentDefault,
+    JustifySelfOverflowAlignmentTrue,
+    JustifySelfOverflowAlignmentSafe
+};
+
 // Reasonable maximum to prevent insane font sizes from causing crashes on some platforms (such as Windows).
 static const float maximumAllowedFontSize = 1000000.0f;