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

Source/core/rendering/style/RenderStyle.h

Index: Source/core/rendering/style/RenderStyle.h
diff --git a/Source/core/rendering/style/RenderStyle.h b/Source/core/rendering/style/RenderStyle.h
index 436a4d5fffca0adf66823c32926934ed90db526a..a1e9355bd66b4feac9620942da9dc4fb68a7cdd9 100644
--- a/Source/core/rendering/style/RenderStyle.h
+++ b/Source/core/rendering/style/RenderStyle.h
@@ -785,6 +785,9 @@ public:
     bool isReverseFlexDirection() const { return flexDirection() == FlowRowReverse || flexDirection() == FlowColumnReverse; }
     EFlexWrap flexWrap() const { return static_cast<EFlexWrap>(rareNonInheritedData->m_flexibleBox->m_flexWrap); }
     EJustifyContent justifyContent() const { return static_cast<EJustifyContent>(rareNonInheritedData->m_justifyContent); }
+    ItemPosition justifyItems() const { return static_cast<ItemPosition>(rareNonInheritedData->m_justifyItems); }
+    OverflowAlignment justifyItemsOverflowAlignment() const { return static_cast<OverflowAlignment>(rareNonInheritedData->m_justifyItemsOverflowAlignment); }
+    LegacyPosition justifyItemsIsLegacy() const { return static_cast<LegacyPosition>(rareNonInheritedData->m_justifyItemsIsLegacy); }
     ItemPosition justifySelf() const { return static_cast<ItemPosition>(rareNonInheritedData->m_justifySelf); }
     OverflowAlignment justifySelfOverflowAlignment() const { return static_cast<OverflowAlignment>(rareNonInheritedData->m_justifySelfOverflowAlignment); }
 
@@ -1264,6 +1267,9 @@ public:
     void setFlexDirection(EFlexDirection direction) { SET_VAR(rareNonInheritedData.access()->m_flexibleBox, m_flexDirection, direction); }
     void setFlexWrap(EFlexWrap w) { SET_VAR(rareNonInheritedData.access()->m_flexibleBox, m_flexWrap, w); }
     void setJustifyContent(EJustifyContent p) { SET_VAR(rareNonInheritedData, m_justifyContent, p); }
+    void setJustifyItems(ItemPosition justifyItems) { SET_VAR(rareNonInheritedData, m_justifyItems, justifyItems); }
+    void setJustifyItemsOverflowAlignment(OverflowAlignment overflowAlignment) { SET_VAR(rareNonInheritedData, m_justifyItemsOverflowAlignment, overflowAlignment); }
+    void setJustifyItemsIsLegacy(LegacyPosition isLegacy) { SET_VAR(rareNonInheritedData, m_justifyItemsIsLegacy, isLegacy); }
     void setJustifySelf(ItemPosition justifySelf) { SET_VAR(rareNonInheritedData, m_justifySelf, justifySelf); }
     void setJustifySelfOverflowAlignment(OverflowAlignment overflowAlignment) { SET_VAR(rareNonInheritedData, m_justifySelfOverflowAlignment, overflowAlignment); }
     void setGridAutoColumns(const GridTrackSize& length) { SET_VAR(rareNonInheritedData.access()->m_grid, m_gridAutoColumns, length); }
@@ -1487,6 +1493,8 @@ public:
     bool isDisplayReplacedType() const { return isDisplayReplacedType(display()); }
     bool isDisplayInlineType() const { return isDisplayInlineType(display()); }
     bool isOriginalDisplayInlineType() const { return isDisplayInlineType(originalDisplay()); }
+    bool isDisplayFlexibleOrGridBox() const { return isDisplayFlexibleBox(display()) || isDisplayGridBox(display()); }
+
 
     bool setWritingMode(WritingMode v)
     {
@@ -1602,6 +1610,8 @@ public:
     static EFlexDirection initialFlexDirection() { return FlowRow; }
     static EFlexWrap initialFlexWrap() { return FlexNoWrap; }
     static EJustifyContent initialJustifyContent() { return JustifyFlexStart; }
+    static ItemPosition initialJustifyItems() { return ItemPositionAuto; }
+    static OverflowAlignment initialJustifyItemsOverflowAlignment() { return OverflowAlignmentDefault; }
     static ItemPosition initialJustifySelf() { return ItemPositionAuto; }
     static OverflowAlignment initialJustifySelfOverflowAlignment() { return OverflowAlignmentDefault; }
     static int initialMarqueeLoopCount() { return -1; }
@@ -1732,6 +1742,16 @@ private:
         return isHorizontalWritingMode() ? getShadowVerticalExtent(shadow, logicalTop, logicalBottom) : getShadowHorizontalExtent(shadow, logicalTop, logicalBottom);
     }
 
+    bool isDisplayFlexibleBox(EDisplay display) const
+    {
+        return display == FLEX || display == INLINE_FLEX;
+    }
+
+    bool isDisplayGridBox(EDisplay display) const
+    {
+        return display == GRID || display == INLINE_GRID;
+    }
+
     bool isDisplayReplacedType(EDisplay display) const
     {
         return display == INLINE_BLOCK || display == INLINE_BOX || display == INLINE_FLEX