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

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

Index: third_party/WebKit/Source/core/css/resolver/StyleResolverState.h
diff --git a/third_party/WebKit/Source/core/css/resolver/StyleResolverState.h b/third_party/WebKit/Source/core/css/resolver/StyleResolverState.h
index f81711704b1f1a135f13223399229f40246de861..fc0ce68faece76a838ed70e1e0f9463af79eb638 100644
--- a/third_party/WebKit/Source/core/css/resolver/StyleResolverState.h
+++ b/third_party/WebKit/Source/core/css/resolver/StyleResolverState.h
@@ -160,6 +160,8 @@ public:
     void setCustomPropertySetForApplyAtRule(const String&, StylePropertySet*);
     StylePropertySet* customPropertySetForApplyAtRule(const String&);
 
+    HeapHashMap<CSSPropertyID, Member<const CSSValue>>& parsedPropertiesForPendingSubstitution(const CSSValue&);
+
 private:
     ElementResolveContext m_elementContext;
     Member<Document> m_document;
@@ -186,6 +188,9 @@ private:
     ElementStyleResources m_elementStyleResources;
 
     HeapHashMap<String, Member<StylePropertySet>> m_customPropertySetsForApplyAtRule;
+
+    HeapHashMap<Member<const CSSValue>, Member<HeapHashMap<CSSPropertyID, Member<const CSSValue>>>> m_parsedPropertiesForPendingSubstitution;

[Timothy Loh, 2016/06/27 04:19:10]

nicer to key on CSSPendingSubstitutionValue

[Andy Mutton, 2016/06/28 03:18:51]

Yeah... I debated this a little, since really this key is just any old pointer
and I tend to like less compile-time dependencies. However, I see the arguments
on the other side and I'm happy to make it explicit. Done.

+
 };
 
 } // namespace blink