More cleanup of dead code now that we don't have frame-level scrolling.

sky/engine/core/frame/UseCounter.cpp

Index: sky/engine/core/frame/UseCounter.cpp
diff --git a/sky/engine/core/frame/UseCounter.cpp b/sky/engine/core/frame/UseCounter.cpp
index 4e8721e7349d01a1e61a1a63d3d6908efaa19143..080e0d923248e11e6b5595afe9b802e13de06c45 100644
--- a/sky/engine/core/frame/UseCounter.cpp
+++ b/sky/engine/core/frame/UseCounter.cpp
@@ -229,9 +229,6 @@ String UseCounter::deprecationMessage(Feature feature)
     case RangeDetach:
         return "'Range.detach' is now a no-op, as per DOM (http://dom.spec.whatwg.org/#dom-range-detach).";
 
-    case OverflowChangedEvent:
-        return "The 'overflowchanged' event is deprecated and may be removed. Please do not use it.";
-
     case HTMLHeadElementProfile:
         return "'HTMLHeadElement.profile' is deprecated. The reflected attribute has no effect.";