Add deprecation warnings to old powerful features on insecure origins.

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)
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
@@ skipping 186 matching lines @@
 {
     // NOTE: the context dispose phase is not supported in oilpan. Please
     // consider using the detach phase instead.
     m_fullScreenElement = nullptr;
     m_fullScreenElementStack.clear();
 }
 #endif
 
 void Fullscreen::requestFullscreen(Element& element, RequestType requestType)
 {
+    // It is required by isPrivilegedContext() but isn't
+    // actually used. This could be used later if a warning is shown in the
+    // developer console.
+    String errorMessage;
+    if (document()->isPrivilegedContext(errorMessage)) {
+        UseCounter::count(document(), UseCounter::FullscreenSecureOrigin);
+    } else {
+        UseCounter::countDeprecation(document(), UseCounter::FullscreenInsecureOrigin);
+    }

[mlamouri (slow - plz ping), 2015/04/30 05:23:53]

No need for { and }

[jww, 2015/04/30 17:28:44]

Done.

+    //    logPowerfulFeatureInsecureOriginWarning(document(), "fullscreen");
+    //}

[mlamouri (slow - plz ping), 2015/04/30 05:23:53]

Remove?

[jww, 2015/04/30 17:28:45]

Yikes, sorry! Done.

+
     // Ignore this request if the document is not in a live frame.
     if (!document()->isActive())
         return;
 
     // If |element| is on top of |doc|'s fullscreen element stack, terminate these substeps.
     if (&element == fullscreenElement())
         return;
 
     do {
         // 1. If any of the following conditions are true, terminate these steps and queue a task to fire
@@ skipping 389 matching lines @@
 DEFINE_TRACE(Fullscreen)
 {
     visitor->trace(m_fullScreenElement);
     visitor->trace(m_fullScreenElementStack);
     visitor->trace(m_eventQueue);
     WillBeHeapSupplement<Document>::trace(visitor);
     DocumentLifecycleObserver::trace(visitor);
 }
 
 } // namespace blink