Add UseCounters for HTMLElement.innerText and .outerText

Source/core/html/HTMLElement.idl

Index: Source/core/html/HTMLElement.idl
diff --git a/Source/core/html/HTMLElement.idl b/Source/core/html/HTMLElement.idl
index 54acf8109882fdd08a9d2bd80ebb966ceb4b06be..ce974470aa7e073a3b93da73131a6bdc8d18c9f0 100644
--- a/Source/core/html/HTMLElement.idl
+++ b/Source/core/html/HTMLElement.idl
@@ -33,8 +33,8 @@
     [Reflect] attribute DOMString accessKey;
 
     // Extensions
-    [TreatNullAs=NullString, CustomElementCallbacks, RaisesException=Setter] attribute DOMString innerText;
-    [TreatNullAs=NullString, CustomElementCallbacks, RaisesException=Setter] attribute DOMString outerText;
+    [TreatNullAs=NullString, CustomElementCallbacks, RaisesException=Setter, MeasureAs=HTMLElementInnerText] attribute DOMString innerText;
+    [TreatNullAs=NullString, CustomElementCallbacks, RaisesException=Setter, MeasureAs=HTMLElementOuterText] attribute DOMString outerText;
 
     [RaisesException, CustomElementCallbacks, MeasureAs=InsertAdjacentElement] Element insertAdjacentElement([Default=Undefined] optional DOMString where,
                                   [Default=Undefined] optional Element element);