[Blink>Fullscreen] Add UseCounter for fullscreen on orientation change

third_party/WebKit/Source/core/dom/Fullscreen.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012 Apple Inc. All
  * rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved.
  * (http://www.torchmobile.com/)
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
@@ skipping 69 matching lines @@
 
 bool allowedToRequestFullscreen(Document& document) {
   // An algorithm is allowed to request fullscreen if one of the following is
   // true:
 
   //  The algorithm is triggered by a user activation.
   if (UserGestureIndicator::utilizeUserGesture())
     return true;
 
   //  The algorithm is triggered by a user generated orientation change.
-  if (ScopedOrientationChangeIndicator::processingOrientationChange())
+  if (ScopedOrientationChangeIndicator::processingOrientationChange()) {
+    UseCounter::count(document,
+                      UseCounter::FullscreenAllowedByOrientationChange);
     return true;
+  }
 
   String message = ExceptionMessages::failedToExecute(
       "requestFullscreen", "Element",
       "API can only be initiated by a user gesture.");
   document.addConsoleMessage(
       ConsoleMessage::create(JSMessageSource, WarningMessageLevel, message));
 
   return false;
 }
 
@@ skipping 660 matching lines @@
 
 DEFINE_TRACE(Fullscreen) {
   visitor->trace(m_currentFullScreenElement);
   visitor->trace(m_fullscreenElementStack);
   visitor->trace(m_eventQueue);
   Supplement<Document>::trace(visitor);
   ContextLifecycleObserver::trace(visitor);
 }
 
 }  // namespace blink