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

Source/core/css/resolver/StyleBuilderCustom.cpp

Index: Source/core/css/resolver/StyleBuilderCustom.cpp
diff --git a/Source/core/css/resolver/StyleBuilderCustom.cpp b/Source/core/css/resolver/StyleBuilderCustom.cpp
index 61f9469503e9409c0ba3b885b951b06d94bc637f..931f706a24100cd80398288ea01c3db982ec1f68 100644
--- a/Source/core/css/resolver/StyleBuilderCustom.cpp
+++ b/Source/core/css/resolver/StyleBuilderCustom.cpp
@@ -43,6 +43,7 @@
 #include "core/StyleBuilderFunctions.h"
 #include "core/StylePropertyShorthand.h"
 #include "core/css/BasicShapeFunctions.h"
+#include "core/css/CSSContentDistributionValue.h"
 #include "core/css/CSSCursorImageValue.h"
 #include "core/css/CSSFontValue.h"
 #include "core/css/CSSGradientValue.h"
@@ -188,6 +189,31 @@ void StyleBuilderFunctions::applyValueCSSPropertyJustifyItems(StyleResolverState
     }
 }
 
+void StyleBuilderFunctions::applyInitialCSSPropertyJustifyContent(StyleResolverState& state)
+{
+    state.style()->setJustifyContent(RenderStyle::initialJustifyContent());
+    state.style()->setJustifyContentOverflowAlignment(RenderStyle::initialJustifyContentOverflowAlignment());
+    state.style()->setJustifyContentDistribution(RenderStyle::initialJustifyContentDistribution());
+}
+
+void StyleBuilderFunctions::applyInheritCSSPropertyJustifyContent(StyleResolverState& state)
+{
+    state.style()->setJustifyContent(state.parentStyle()->justifyContent());
+    state.style()->setJustifyContentOverflowAlignment(state.parentStyle()->justifyContentOverflowAlignment());
+    state.style()->setJustifyContentDistribution(state.parentStyle()->justifyContentDistribution());
+}
+
+void StyleBuilderFunctions::applyValueCSSPropertyJustifyContent(StyleResolverState& state, CSSValue* value)
+{
+    CSSContentDistributionValue* contentValue = toCSSContentDistributionValue(value);
+    if (contentValue->distribution()->getValueID() != CSSValueInvalid)
+        state.style()->setJustifyContentDistribution(*contentValue->distribution());
+    if (contentValue->position()->getValueID() != CSSValueInvalid)
+        state.style()->setJustifyContent(*contentValue->position());
+    if (contentValue->overflow()->getValueID() != CSSValueInvalid)
+        state.style()->setJustifyContentOverflowAlignment(*contentValue->overflow());
+}
+
 void StyleBuilderFunctions::applyInitialCSSPropertyCursor(StyleResolverState& state)
 {
     state.style()->clearCursorList();