Introduce use counters for shadow DOM handling in plainText()

Source/core/dom/Element.cpp

Index: Source/core/dom/Element.cpp
diff --git a/Source/core/dom/Element.cpp b/Source/core/dom/Element.cpp
index 6c7e86884a4cdeaabab5c23d3a5e7179cac6bffe..85e3cac75909a1c28968bc646f0ac8497a31723a 100644
--- a/Source/core/dom/Element.cpp
+++ b/Source/core/dom/Element.cpp
@@ -2497,7 +2497,7 @@ String Element::innerText()
     if (!layoutObject())
         return textContent(true);
 
-    return plainText(Position(this, PositionAnchorType::BeforeChildren), Position(this, PositionAnchorType::AfterChildren));
+    return plainText(Position(this, PositionAnchorType::BeforeChildren), Position(this, PositionAnchorType::AfterChildren), TextIteratorForInnerText);
 }
 
 String Element::outerText()