Make default for deep parameter in importNode false

Source/core/frame/UseCounter.cpp

Index: Source/core/frame/UseCounter.cpp
diff --git a/Source/core/frame/UseCounter.cpp b/Source/core/frame/UseCounter.cpp
index ead539dbcf924b3aacf8b8c3dbede2b9d6d4fd70..e35d4b0d1ac6d19b7300e8a8d365069dcc5117cb 100644
--- a/Source/core/frame/UseCounter.cpp
+++ b/Source/core/frame/UseCounter.cpp
@@ -712,6 +712,10 @@ String UseCounter::deprecationMessage(Feature feature)
     case ElementSetAttributeNodeNS:
         return "'Element.setAttributeNodeNS' is deprecated and has been removed from DOM4 (http://w3.org/tr/dom).";
 
+    case DocumentImportNodeOptionalArgument:
+        return "The behavior of importNode() with no boolean argument is about to change from doing a deep clone to doing a shallow clone.  "
+            "Make sure to pass an explicit boolean argument to keep your current behavior.";
+
     // Features that aren't deprecated don't have a deprecation message.
     default:
         return String();