[CSS Grid Layout] Stretch value for align and justify properties.

Source/core/css/resolver/StyleAdjuster.cpp

Index: Source/core/css/resolver/StyleAdjuster.cpp
diff --git a/Source/core/css/resolver/StyleAdjuster.cpp b/Source/core/css/resolver/StyleAdjuster.cpp
index cce0938458ab0b7838fbc8fc4700fc618de0850f..477002f3ed6deb81eea530bd7e7f1754b4a91f64 100644
--- a/Source/core/css/resolver/StyleAdjuster.cpp
+++ b/Source/core/css/resolver/StyleAdjuster.cpp
@@ -301,8 +301,11 @@ void StyleAdjuster::adjustStyleForAlignment(RenderStyle& style, const RenderStyl
     // Flex Containers: 'auto' computes to 'flex-start'.
     // Grid Containers: 'auto' computes to 'start', and 'stretch' behaves like 'start'.
     if ((style.justifyContent() == ContentPositionAuto) && (style.justifyContentDistribution() == ContentDistributionDefault)) {
-        if (style.isDisplayFlexibleBox()) {
-            style.setJustifyContent(ContentPositionFlexStart);
+        if (style.isDisplayFlexibleOrGridBox()) {
+            if (style.isDisplayFlexibleBox())
+                style.setJustifyContent(ContentPositionFlexStart);
+            else
+                style.setJustifyContent(ContentPositionStart);
         }
     }
 }