Add expansion of shorthands with custom properties to longhands using a pending substition value.

third_party/WebKit/Source/core/css/resolver/StyleResolverState.cpp

Index: third_party/WebKit/Source/core/css/resolver/StyleResolverState.cpp
diff --git a/third_party/WebKit/Source/core/css/resolver/StyleResolverState.cpp b/third_party/WebKit/Source/core/css/resolver/StyleResolverState.cpp
index 6fc6c070d179659be1265f482642ca16d1119922..4f596b88904140c020b2207f27a827f57fc597e0 100644
--- a/third_party/WebKit/Source/core/css/resolver/StyleResolverState.cpp
+++ b/third_party/WebKit/Source/core/css/resolver/StyleResolverState.cpp
@@ -86,4 +86,14 @@ StylePropertySet* StyleResolverState::customPropertySetForApplyAtRule(const Stri
     return m_customPropertySetsForApplyAtRule.get(string);
 }
 
+void StyleResolverState::setCssValueForLonghandPropertyId(CSSPropertyID longhandPropertyId, const CSSValue* cssValue)
+{
+    m_parsedLonghandCssValueForVariableResolver.set(longhandPropertyId, cssValue);
+}
+
+const CSSValue* StyleResolverState::cssValueForLonghandPropertyId(CSSPropertyID longhandPropertyId)
+{
+    return m_parsedLonghandCssValueForVariableResolver.get(longhandPropertyId);
+}
+
 } // namespace blink