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

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

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CSSVariableResolver_h
 #define CSSVariableResolver_h
 
 #include "core/CSSPropertyNames.h"
 #include "core/css/parser/CSSParserToken.h"
 #include "wtf/HashSet.h"
 #include "wtf/text/AtomicString.h"
 #include "wtf/text/AtomicStringHash.h"
 
 namespace blink {
 
 class CSSParserTokenRange;
+class CSSPendingSubstitutionValue;
 class CSSVariableData;
 class CSSVariableReferenceValue;
 class StyleResolverState;
 class StyleVariableData;
 
 class CSSVariableResolver {
 public:
     static void resolveVariableDefinitions(StyleVariableData*);
-    static void resolveAndApplyVariableReferences(StyleResolverState&, CSSPropertyID, const CSSVariableReferenceValue&);
+    static const CSSValue* resolveVariableReferences(StyleResolverState&, CSSPropertyID, const CSSVariableReferenceValue&);
+    static const CSSValue* resolvePendingSubstitutions(StyleResolverState&, CSSPropertyID, const CSSPendingSubstitutionValue&);
 
     // Shorthand properties are not supported.
     static CSSValue* resolveVariableReferences(StyleVariableData*, CSSPropertyID, const CSSVariableReferenceValue&);
 
 private:
     CSSVariableResolver(StyleVariableData*);
 
     // These return false if we encounter a reference to an invalid variable with no fallback
 
     // Resolves a range which may contain var() references or @apply rules
@@ skipping 16 matching lines @@
     HashSet<AtomicString> m_variablesSeen;
     // Resolution doesn't finish when a cycle is detected. Fallbacks still
     // need to be tracked for additional cycles, and invalidation only
     // applies back to cycle starts.
     HashSet<AtomicString> m_cycleStartPoints;
 };
 
 } // namespace blink
 
 #endif // CSSVariableResolver