Add three UseCounters for LABEL element.

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2010 Apple Inc. All rights reserved.
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  *
  * 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
@@ skipping 16 matching lines @@
 #include "core/HTMLNames.h"
 #include "core/dom/Document.h"
 #include "core/dom/ElementTraversal.h"
 #include "core/editing/EditingUtilities.h"
 #include "core/editing/FrameSelection.h"
 #include "core/editing/SelectionController.h"
 #include "core/events/MouseEvent.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/UseCounter.h"
 #include "core/html/FormAssociatedElement.h"
+#include "core/html/HTMLFormControlElement.h"
 #include "core/input/EventHandler.h"
 #include "core/layout/LayoutObject.h"
 
 namespace blink {
 
 using namespace HTMLNames;
 
 inline HTMLLabelElement::HTMLLabelElement(Document& document, HTMLFormElement* form)
     : HTMLElement(labelTag, document)
     , m_processingClick(false)
 {
     FormAssociatedElement::associateByParser(form);
 }
 
 PassRefPtrWillBeRawPtr<HTMLLabelElement> HTMLLabelElement::create(Document& document, HTMLFormElement* form)
 {
     RefPtrWillBeRawPtr<HTMLLabelElement> labelElement = adoptRefWillBeNoop(new HTMLLabelElement(document, form));
     return labelElement.release();
 }
 
 LabelableElement* HTMLLabelElement::control() const
 {
     const AtomicString& controlId = getAttribute(forAttr);
     if (controlId.isNull()) {
         // Search the children and descendants of the label element for a form element.
         // per http://dev.w3.org/html5/spec/Overview.html#the-label-element
         // the form element must be "labelable form-associated element".
         for (LabelableElement& element : Traversal<LabelableElement>::descendantsOf(*this)) {
-            if (element.supportLabels())
+            if (element.supportLabels()) {
+                if (!element.isFormControlElement())
+                    UseCounter::count(document(), UseCounter::HTMLLabelElementControlForNonFormAssociatedElement);
                 return &element;
+            }
         }
         return nullptr;
     }
 
     if (Element* element = treeScope().getElementById(controlId)) {
-        if (isLabelableElement(*element) && toLabelableElement(*element).supportLabels())
+        if (isLabelableElement(*element) && toLabelableElement(*element).supportLabels()) {
+            if (!element->isFormControlElement())
+                UseCounter::count(document(), UseCounter::HTMLLabelElementControlForNonFormAssociatedElement);
             return toLabelableElement(element);
+        }
     }
 
     return nullptr;
 }
 
 HTMLFormElement* HTMLLabelElement::formOwner() const
 {
     return FormAssociatedElement::form();
 }
 
+HTMLFormElement* HTMLLabelElement::formForBinding() const
+{
+    HTMLFormElement* formOwner = FormAssociatedElement::form();
+    HTMLFormElement* controlForm = nullptr;
+    if (LabelableElement* control = this->control()) {
+        if (control->isFormControlElement())
+            controlForm = toHTMLFormControlElement(control)->form();
+    }
+    if (formOwner != controlForm)
+        UseCounter::count(document(), UseCounter::HTMLLabelElementFormIsDifferentFromControlForm);
+    if (!controlForm && formOwner && formOwner == findFormAncestor())
+        UseCounter::count(document(), UseCounter::HTMLLabelElementHasNoControlAndFormIsAncestor);
+    return formOwner;
+}
+
 void HTMLLabelElement::setActive(bool down)
 {
     if (down != active()) {
         // Update our status first.
         HTMLElement::setActive(down);
     }
 
     // Also update our corresponding control.
     HTMLElement* controlElement = control();
     if (controlElement && controlElement->active() != active())
@@ skipping 185 matching lines @@
         if (attributeName == forAttr) {
             TreeScope& scope = treeScope();
             if (scope.shouldCacheLabelsByForAttribute())
                 updateLabel(scope, oldValue, attributeValue);
         }
         HTMLElement::parseAttribute(attributeName, oldValue, attributeValue);
     }
 }
 
 } // namespace blink