Support interpolation of animatable shorthand properties containing var()

third_party/WebKit/Source/core/animation/StringKeyframe.cpp

Index: third_party/WebKit/Source/core/animation/StringKeyframe.cpp
diff --git a/third_party/WebKit/Source/core/animation/StringKeyframe.cpp b/third_party/WebKit/Source/core/animation/StringKeyframe.cpp
index 5d3f3accb1c857bf07a356e5bbd2503a9571b2d7..0d1fc97dd6a4be09bc81ef9e0b6312c2d21494ee 100644
--- a/third_party/WebKit/Source/core/animation/StringKeyframe.cpp
+++ b/third_party/WebKit/Source/core/animation/StringKeyframe.cpp
@@ -55,8 +55,7 @@ PropertyHandleSet StringKeyframe::properties() const
     PropertyHandleSet properties;
     for (unsigned i = 0; i < m_cssPropertyMap->propertyCount(); ++i) {
         StylePropertySet::PropertyReference propertyReference = m_cssPropertyMap->propertyAt(i);
-        DCHECK(
-            !isShorthandProperty(propertyReference.id()) || propertyReference.value().isVariableReferenceValue())
+        DCHECK(!isShorthandProperty(propertyReference.id()))
             << "Web Animations: Encountered unexpanded shorthand CSS property (" << propertyReference.id() << ").";
         properties.add(PropertyHandle(propertyReference.id(), false));
     }