Add CSS Transition support to registered custom properties

third_party/WebKit/Source/core/css/CSSPropertyEquality.h

Index: third_party/WebKit/Source/core/css/CSSPropertyEquality.h
diff --git a/third_party/WebKit/Source/core/css/CSSPropertyEquality.h b/third_party/WebKit/Source/core/css/CSSPropertyEquality.h
index d70e8cfcd1b162315aa77f95e1143bdf3d81f3f8..bf75be335cccf90070627e2abeb4f1595e149fdf 100644
--- a/third_party/WebKit/Source/core/css/CSSPropertyEquality.h
+++ b/third_party/WebKit/Source/core/css/CSSPropertyEquality.h
@@ -7,6 +7,7 @@
 
 #include "core/CSSPropertyNames.h"
 #include "wtf/Allocator.h"
+#include "wtf/text/AtomicString.h"
 
 namespace blink {
 
@@ -19,6 +20,11 @@ class CSSPropertyEquality {
   static bool propertiesEqual(CSSPropertyID,
                               const ComputedStyle&,
                               const ComputedStyle&);
+
+  static bool registeredCustomPropertiesEqual(
+      const WTF::AtomicString& propertyName,
+      const ComputedStyle&,
+      const ComputedStyle&);
 };
 
 }  // namespace blink