Add detailed use counters for document.registerElement use.

third_party/WebKit/Source/core/dom/custom/V0CustomElement.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 20 matching lines @@
 #include "core/dom/custom/V0CustomElement.h"
 
 #include "core/HTMLNames.h"
 #include "core/MathMLNames.h"
 #include "core/SVGNames.h"
 #include "core/dom/Document.h"
 #include "core/dom/Element.h"
 #include "core/dom/custom/V0CustomElementMicrotaskRunQueue.h"
 #include "core/dom/custom/V0CustomElementObserver.h"
 #include "core/dom/custom/V0CustomElementScheduler.h"
+#include "core/frame/UseCounter.h"
 
 namespace blink {
 
 V0CustomElementMicrotaskImportStep* V0CustomElement::didCreateImport(
     HTMLImportChild* import) {
   return V0CustomElementScheduler::scheduleImport(import);
 }
 
 void V0CustomElement::didFinishLoadingImport(Document& master) {
   master.customElementMicrotaskRunQueue()->requestDispatchIfNeeded();
@@ skipping 50 matching lines @@
 
 void V0CustomElement::define(Element* element,
                              V0CustomElementDefinition* definition) {
   switch (element->getV0CustomElementState()) {
     case Element::V0NotCustomElement:
     case Element::V0Upgraded:
       NOTREACHED();
       break;
 
     case Element::V0WaitingForUpgrade:
+      UseCounter::count(
+          element->document(),
+          definition->descriptor().isTypeExtension()
+              ? UseCounter::V0CustomElementsCreateTypeExtensionElement
+              : UseCounter::V0CustomElementsCreateCustomTagElement);
       element->v0SetCustomElementDefinition(definition);
       V0CustomElementScheduler::scheduleCallback(
           definition->callbacks(), element,
           V0CustomElementLifecycleCallbacks::CreatedCallback);
       break;
   }
 }
 
 void V0CustomElement::attributeDidChange(Element* element,
                                          const AtomicString& name,
@@ skipping 30 matching lines @@
       break;
 
     case Element::V0WaitingForUpgrade:
     case Element::V0Upgraded:
       V0CustomElementObserver::notifyElementWasDestroyed(element);
       break;
   }
 }
 
 }  // namespace blink