[CSS Grid Layout] Upgrade justify-content parsing to CSS3 Box Alignment spec.

Source/core/css/parser/CSSPropertyParser.cpp

Index: Source/core/css/parser/CSSPropertyParser.cpp
diff --git a/Source/core/css/parser/CSSPropertyParser.cpp b/Source/core/css/parser/CSSPropertyParser.cpp
index b1e2d1cc5495c2fe930e1888fa1f0c29ba8014eb..b948ca76ea24851283bd76c3ca56eeb61574f5c7 100644
--- a/Source/core/css/parser/CSSPropertyParser.cpp
+++ b/Source/core/css/parser/CSSPropertyParser.cpp
@@ -33,6 +33,7 @@
 #include "core/css/CSSBasicShapes.h"
 #include "core/css/CSSBorderImage.h"
 #include "core/css/CSSCanvasValue.h"
+#include "core/css/CSSContentDistributionValue.h"
 #include "core/css/CSSCrossfadeValue.h"
 #include "core/css/CSSCursorImageValue.h"
 #include "core/css/CSSFontFaceSrcValue.h"
@@ -1202,6 +1203,9 @@ bool CSSPropertyParser::parseValue(CSSPropertyID propId, bool important)
         return false;
     }
 
+    case CSSPropertyJustifyContent:
+        parsedValue = parseContentDistributionOverflowPosition();
+        break;
     case CSSPropertyJustifySelf:
         ASSERT(RuntimeEnabledFeatures::cssGridLayoutEnabled());
         return parseItemPositionOverflowPosition(propId, important);
@@ -4029,11 +4033,29 @@ PassRefPtrWillBeRawPtr<CSSBasicShape> CSSPropertyParser::parseBasicShapeInset(CS
     return shape;
 }
 
+static bool isContentDistributionKeyword(CSSValueID id)
+{
+    return id == CSSValueSpaceBetween || id == CSSValueSpaceAround
+        || id == CSSValueSpaceEvenly || id == CSSValueStretch;
+}
+
+static bool isContentPositionKeyword(CSSValueID id)
+{
+    return id == CSSValueStart || id == CSSValueEnd || id == CSSValueCenter
+        || id == CSSValueFlexStart || id == CSSValueFlexEnd
+        || id == CSSValueLeft || id == CSSValueRight;
+}
+
 static bool isBaselinePositionKeyword(CSSValueID id)
 {
     return id == CSSValueBaseline || id == CSSValueLastBaseline;
 }
 
+static bool isAlignmentOverflowKeyword(CSSValueID id)
+{
+    return id == CSSValueTrue || id == CSSValueSafe;
+}
+
 static bool isItemPositionKeyword(CSSValueID id)
 {
     return id == CSSValueStart || id == CSSValueEnd || id == CSSValueCenter
@@ -4066,6 +4088,50 @@ bool CSSPropertyParser::parseLegacyPosition(CSSPropertyID propId, bool important
     return !m_valueList->next();
 }
 
+PassRefPtrWillBeRawPtr<CSSValue> CSSPropertyParser::parseContentDistributionOverflowPosition()
+{
+    // auto | <baseline-position> | [ <content-distribution>? && <content-position>? ]! && <overflow-position>?
+    // <baseline-position> = baseline | last-baseline;
+    // <content-distribution> = space-between | space-around | space-evenly | stretch;
+    // <content-position> = center | start | end | flex-start | flex-end | left | right;
+    // <overflow-position> = true | safe
+
+    // auto | <baseline-position>
+    CSSParserValue* value = m_valueList->current();
+    if (value->id == CSSValueAuto || isBaselinePositionKeyword(value->id)) {
+        m_valueList->next();
+        return CSSContentDistributionValue::create(CSSValueInvalid, value->id, CSSValueInvalid);
+    }
+
+    CSSValueID distribution = CSSValueInvalid;
+    CSSValueID position = CSSValueInvalid;
+    CSSValueID overflow = CSSValueInvalid;
+    if (isAlignmentOverflowKeyword(value->id)) {
+        overflow = value->id;
+        value = m_valueList->next();
+    }
+    if (value && isContentDistributionKeyword(value->id)) {
+        distribution = value->id;
+        value = m_valueList->next();
+    }
+    if (value && isContentPositionKeyword(value->id)) {
+        position = value->id;
+        value = m_valueList->next();
+    }
+    if (value) {
+        if (overflow != CSSValueInvalid || !isAlignmentOverflowKeyword(value->id))
+            return nullptr;
+        overflow = value->id;
+    }
+
+    // The grammar states that we should have at least <content-distribution> or
+    // <content-position> ([ <content-distribution>? && <content-position>? ]!).
+    if (m_valueList->next() || (position == CSSValueInvalid && distribution == CSSValueInvalid))
+        return nullptr;
+
+    return CSSContentDistributionValue::create(distribution, position, overflow);
+}
+
 bool CSSPropertyParser::parseItemPositionOverflowPosition(CSSPropertyID propId, bool important)
 {
     // auto | stretch | <baseline-position> | [<item-position> && <overflow-position>? ]
@@ -4091,12 +4157,12 @@ bool CSSPropertyParser::parseItemPositionOverflowPosition(CSSPropertyID propId,
         position = cssValuePool().createIdentifierValue(value->id);
         value = m_valueList->next();
         if (value) {
-            if (value->id == CSSValueTrue || value->id == CSSValueSafe)
+            if (isAlignmentOverflowKeyword(value->id))
                 overflowAlignmentKeyword = cssValuePool().createIdentifierValue(value->id);
             else
                 return false;
         }
-    } else if (value->id == CSSValueTrue || value->id == CSSValueSafe) {
+    } else if (isAlignmentOverflowKeyword(value->id)) {
         overflowAlignmentKeyword = cssValuePool().createIdentifierValue(value->id);
         value = m_valueList->next();
         if (value && isItemPositionKeyword(value->id))