Revert of Sync requestFullscreen() and exitFullscreen() algorithms with the spec

third_party/WebKit/Source/modules/vr/VRDisplay.cpp

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "modules/vr/VRDisplay.h"
 
 #include "core/css/StylePropertySet.h"
 #include "core/dom/DOMException.h"
 #include "core/dom/DocumentUserGestureToken.h"
 #include "core/dom/FrameRequestCallback.h"
@@ skipping 692 matching lines @@
 void VRDisplay::onFullscreenCheck(TimerBase*) {
   if (!m_isPresenting) {
     m_fullscreenCheckTimer.stop();
     return;
   }
   // TODO: This is a temporary measure to track if fullscreen mode has been
   // exited by the UA. If so we need to end VR presentation. Soon we won't
   // depend on the Fullscreen API to fake VR presentation, so this will
   // become unnessecary. Until that point, though, this seems preferable to
   // adding a bunch of notification plumbing to Fullscreen.
-  if (!Fullscreen::isFullscreenElement(*m_layer.source())) {
+  if (!Fullscreen::isCurrentFullScreenElement(*m_layer.source())) {
     // TODO(mthiesse): Due to asynchronous resizing, we might get kicked out of
     // fullscreen when changing display parameters upon entering WebVR. So one
     // time only, we reenter fullscreen after having left it; otherwise we exit
     // presentation.
     if (m_reenteredFullscreen) {
       m_isPresenting = false;
       OnPresentChange();
       m_fullscreenCheckTimer.stop();
       if (m_display)
         m_display->ExitPresent();
@@ skipping 51 matching lines @@
   visitor->trace(m_stageParameters);
   visitor->trace(m_eyeParametersLeft);
   visitor->trace(m_eyeParametersRight);
   visitor->trace(m_layer);
   visitor->trace(m_renderingContext);
   visitor->trace(m_scriptedAnimationController);
   visitor->trace(m_pendingPresentResolvers);
 }
 
 }  // namespace blink