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

third_party/WebKit/Source/core/style/ComputedStyle.h

Index: third_party/WebKit/Source/core/style/ComputedStyle.h
diff --git a/third_party/WebKit/Source/core/style/ComputedStyle.h b/third_party/WebKit/Source/core/style/ComputedStyle.h
index f0550f586803e7bcf303af24dc25b042f1f16532..3c86329aa3c095ceae4acee816261c9b7be4da7d 100644
--- a/third_party/WebKit/Source/core/style/ComputedStyle.h
+++ b/third_party/WebKit/Source/core/style/ComputedStyle.h
@@ -472,7 +472,7 @@ public:
     // Non-Inherited properties.
 
     // Content alignment properties.
-    static StyleContentAlignmentData initialContentAlignment() { return StyleContentAlignmentData(RuntimeEnabledFeatures::cssGridLayoutEnabled() ? ContentPositionNormal : ContentPositionFlexStart, ContentDistributionDefault, OverflowAlignmentDefault); }
+    static StyleContentAlignmentData initialContentAlignment() { return StyleContentAlignmentData(ContentPositionNormal, ContentDistributionDefault, OverflowAlignmentDefault); }
 
     // align-content (aka -webkit-align-content)
     const StyleContentAlignmentData& alignContent() const { return m_rareNonInheritedData->m_alignContent; }