Remove unnecessary sync style recalc for fullscreen.

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 422 matching lines @@
     if (shouldCreatePlaceholder) {
         m_savedPlaceholderFrameRect = toRenderBox(renderer)->frameRect();
         m_savedPlaceholderRenderStyle = RenderStyle::clone(renderer->style());
     }
 
     if (m_fullScreenElement != document()->documentElement())
         RenderFullScreen::wrapRenderer(renderer, renderer ? renderer->parent() : 0, document());
 
     m_fullScreenElement->setContainsFullScreenElementOnAncestorsCrossingFrameBoundaries(true);
 
-    // FIXME: This should not call updateStyleIfNeeded.
     document()->setNeedsStyleRecalc(SubtreeStyleChange, StyleChangeReasonForTracing::create(StyleChangeReason::FullScreen));
-    document()->updateRenderTreeIfNeeded();
 
     m_fullScreenElement->didBecomeFullscreenElement();
 
     if (document()->frame())
         document()->frame()->eventHandler().scheduleHoverStateUpdate();
 
     m_eventQueueTimer.startOneShot(0, FROM_HERE);
 }
 
 void Fullscreen::didExitFullScreenForElement(Element*)
@@ skipping 148 matching lines @@
 void Fullscreen::trace(Visitor* visitor)
 {
     visitor->trace(m_fullScreenElement);
     visitor->trace(m_fullScreenElementStack);
     visitor->trace(m_fullScreenRenderer);
     visitor->trace(m_eventQueue);
     DocumentSupplement::trace(visitor);
 }
 
 } // namespace blink