Measure the usage of <ol>.start with |reversed| and no |start| attribute.

third_party/WebKit/Source/core/html/HTMLOListElement.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2010 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 78 matching lines @@
     bool reversed = !params.new_value.IsNull();
     if (reversed == is_reversed_)
       return;
     is_reversed_ = reversed;
     UpdateItemValues();
   } else {
     HTMLElement::ParseAttribute(params);
   }
 }
 
+int HTMLOListElement::start() const {
+  if (has_explicit_start_)
+    return start_;
+
+  if (is_reversed_) {
+    UseCounter::Count(
+        GetDocument(),
+        UseCounter::kHTMLOListElementStartGetterReversedWithoutStartAttribute);
+    return ItemCount();
+  }
+
+  return 1;
+}
+
 void HTMLOListElement::setStart(int start) {
   SetIntegralAttribute(startAttr, start);
 }
 
 void HTMLOListElement::UpdateItemValues() {
   if (!GetLayoutObject())
     return;
   UpdateDistribution();
   LayoutListItem::UpdateItemValuesForOrderedList(this);
 }
 
 void HTMLOListElement::RecalculateItemCount() {
   item_count_ = LayoutListItem::ItemCountForOrderedList(this);
   should_recalculate_item_count_ = false;
 }
 
 }  // namespace blink