[css-align] Initial value of align-content should be 'stretch'.

third_party/WebKit/Source/core/css/ComputedStyleCSSValueMapping.cpp

 /*
  * Copyright (C) 2004 Zack Rusin <zack@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
  * Copyright (C) 2007 Nicholas Shanks <webkit@nickshanks.com>
  * Copyright (C) 2011 Sencha, Inc. All rights reserved.
  * Copyright (C) 2015 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ skipping 532 matching lines @@
         CSSValueList* afterSlash = CSSValueList::createSpaceSeparated();
         afterSlash->append(*valueForFillSize(currLayer->size(), style));
         afterSlash->append(*CSSPrimitiveValue::create(currLayer->origin()));
         afterSlash->append(*CSSPrimitiveValue::create(currLayer->clip()));
         list->append(*afterSlash);
         ret->append(*list);
     }
     return ret;
 }
 
-static CSSValueList* valueForContentPositionAndDistributionWithOverflowAlignment(const StyleContentAlignmentData& data)
+static CSSValueList* valueForContentPositionAndDistributionWithOverflowAlignment(const StyleContentAlignmentData& data, CSSValueID normalBehaviorValueID)
 {
     CSSValueList* result = CSSValueList::createSpaceSeparated();
     if (data.distribution() != ContentDistributionDefault)
         result->append(*CSSPrimitiveValue::create(data.distribution()));
-    if (data.distribution() == ContentDistributionDefault || data.position() != ContentPositionNormal)
-        result->append(*CSSPrimitiveValue::create(data.position()));
+    if (data.distribution() == ContentDistributionDefault || data.position() != ContentPositionNormal) {
+        if (!RuntimeEnabledFeatures::cssGridLayoutEnabled() && data.position() == ContentPositionNormal)
+            result->append(*CSSPrimitiveValue::createIdentifier(normalBehaviorValueID));
+        else
+            result->append(*CSSPrimitiveValue::create(data.position()));
+    }
     if ((data.position() >= ContentPositionCenter || data.distribution() != ContentDistributionDefault) && data.overflow() != OverflowAlignmentDefault)
         result->append(*CSSPrimitiveValue::create(data.overflow()));
     ASSERT(result->length() > 0);
     ASSERT(result->length() <= 3);
     return result;
 }
 
 static CSSPrimitiveValue* valueForLineHeight(const ComputedStyle& style)
 {
     Length length = style.lineHeight();
@@ skipping 1314 matching lines @@
         }
         return value;
     }
     case CSSPropertyDirection:
         return CSSPrimitiveValue::create(style.direction());
     case CSSPropertyDisplay:
         return CSSPrimitiveValue::create(style.display());
     case CSSPropertyEmptyCells:
         return CSSPrimitiveValue::create(style.emptyCells());
     case CSSPropertyAlignContent:
-        return valueForContentPositionAndDistributionWithOverflowAlignment(style.alignContent());
+        return valueForContentPositionAndDistributionWithOverflowAlignment(style.alignContent(), CSSValueStretch);
     case CSSPropertyAlignItems:
         return valueForItemPositionWithOverflowAlignment(style.alignItems());
     case CSSPropertyAlignSelf:
         return valueForItemPositionWithOverflowAlignment(style.alignSelf());
     case CSSPropertyFlex:
         return valuesForShorthandProperty(flexShorthand(), style, layoutObject, styledNode, allowVisitedStyle);
     case CSSPropertyFlexBasis:
         return zoomAdjustedPixelValueForLength(style.flexBasis(), style);
     case CSSPropertyFlexDirection:
         return CSSPrimitiveValue::create(style.flexDirection());
     case CSSPropertyFlexFlow:
         return valuesForShorthandProperty(flexFlowShorthand(), style, layoutObject, styledNode, allowVisitedStyle);
     case CSSPropertyFlexGrow:
         return CSSPrimitiveValue::create(style.flexGrow(), CSSPrimitiveValue::UnitType::Number);
     case CSSPropertyFlexShrink:
         return CSSPrimitiveValue::create(style.flexShrink(), CSSPrimitiveValue::UnitType::Number);
     case CSSPropertyFlexWrap:
         return CSSPrimitiveValue::create(style.flexWrap());
     case CSSPropertyJustifyContent:
-        return valueForContentPositionAndDistributionWithOverflowAlignment(style.justifyContent());
+        return valueForContentPositionAndDistributionWithOverflowAlignment(style.justifyContent(), CSSValueFlexStart);
     case CSSPropertyOrder:
         return CSSPrimitiveValue::create(style.order(), CSSPrimitiveValue::UnitType::Number);
     case CSSPropertyFloat:
         if (style.display() != NONE && style.hasOutOfFlowPosition())
             return CSSPrimitiveValue::createIdentifier(CSSValueNone);
         return CSSPrimitiveValue::create(style.floating());
     case CSSPropertyFont:
         return valueForFont(style);
     case CSSPropertyFontFamily:
         return valueForFontFamily(style);
@@ skipping 1084 matching lines @@
     case CSSPropertyAll:
         return nullptr;
     default:
         break;
     }
     ASSERT_NOT_REACHED();
     return nullptr;
 }
 
 } // namespace blink