Add metrics for usage of permission features from iframes in blink

third_party/WebKit/Source/core/page/PointerLockController.cpp

 /*
  * Copyright (C) 2012 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
  *     notice, this list of conditions and the following disclaimer in the
@@ skipping 34 matching lines @@
     return adoptPtrWillBeNoop(new PointerLockController(page));
 }
 
 void PointerLockController::requestPointerLock(Element* target)
 {
     if (!target || !target->inDocument() || m_documentOfRemovedElementWhileWaitingForUnlock) {
         enqueueEvent(EventTypeNames::pointerlockerror, target);
         return;
     }
 
+    UseCounter::countCrossOriginIframe(target->document(), UseCounter::ElementRequestPointerLockIframe);
+
     if (target->document().isSandboxed(SandboxPointerLock)) {
         // FIXME: This message should be moved off the console once a solution to https://bugs.webkit.org/show_bug.cgi?id=103274 exists.
         target->document().addConsoleMessage(ConsoleMessage::create(SecurityMessageSource, ErrorMessageLevel, "Blocked pointer lock on an element because the element's frame is sandboxed and the 'allow-pointer-lock' permission is not set."));
         enqueueEvent(EventTypeNames::pointerlockerror, target);
         return;
     }
 
     if (m_element) {
         if (m_element->document() != target->document()) {
             enqueueEvent(EventTypeNames::pointerlockerror, target);
@@ skipping 93 matching lines @@
 }
 
 DEFINE_TRACE(PointerLockController)
 {
     visitor->trace(m_page);
     visitor->trace(m_element);
     visitor->trace(m_documentOfRemovedElementWhileWaitingForUnlock);
 }
 
 } // namespace blink