Revert "Switch MutationEvents UseCounter to use countDeprecation."

Source/core/page/UseCounter.cpp

Index: Source/core/page/UseCounter.cpp
diff --git a/Source/core/page/UseCounter.cpp b/Source/core/page/UseCounter.cpp
index 22c5cd0ea1e3b3223c2646e872330186abb3a0c4..5db2ae9ea987d0ab5a34cb6b64c75556c12c63d7 100644
--- a/Source/core/page/UseCounter.cpp
+++ b/Source/core/page/UseCounter.cpp
@@ -670,24 +670,6 @@ String UseCounter::deprecationMessage(Feature feature)
     case EventReturnValue:
         return "event.returnValue is deprecated. Please use the standard event.preventDefault() instead.";
 
-    case DOMSubtreeModifiedEvent:
-        return "DOMSubtreeModified is deprecated. Use MutationObservers instead.";
-
-    case DOMNodeInsertedEvent:
-        return "DOMNodeInserted is deprecated. Use MutationObservers instead.";
-
-    case DOMNodeRemovedEvent:
-        return "DOMNodeRemoved is deprecated. Use MutationObservers instead.";
-
-    case DOMNodeRemovedFromDocumentEvent:
-        return "DOMNodeRemovedFromDocument is deprecated. Use MutationObservers instead.";
-
-    case DOMNodeInsertedIntoDocumentEvent:
-        return "DOMNodeInsertedIntoDocument is deprecated. Use MutationObservers instead.";
-
-    case DOMCharacterDataModifiedEvent:
-        return "DOMCharacterDataModified is deprecated. Use MutationObservers instead.";
-
     // Features that aren't deprecated don't have a deprecation message.
     default:
         return String();