Rename default -> initial style and use singletons.

Source/core/layout/LayoutFullScreen.cpp

 /*
  * Copyright (C) 2010 Apple 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 72 matching lines @@
     // if its LayoutFullScreen is destroyed.
     Fullscreen& fullscreen = Fullscreen::from(document());
     if (fullscreen.fullScreenRenderer() == this)
         fullscreen.fullScreenRendererDestroyed();
 
     LayoutFlexibleBox::willBeDestroyed();
 }
 
 void LayoutFullScreen::updateStyle()
 {
-    RefPtr<LayoutStyle> fullscreenStyle = LayoutStyle::createDefaultStyle();
+    RefPtr<LayoutStyle> fullscreenStyle = LayoutStyle::create();
 
     // Create a stacking context:
     fullscreenStyle->setZIndex(INT_MAX);
 
     fullscreenStyle->setFontDescription(FontDescription());
     fullscreenStyle->font().update(nullptr);
 
     fullscreenStyle->setDisplay(FLEX);
     fullscreenStyle->setJustifyContent(ContentPositionCenter);
     fullscreenStyle->setAlignItems(ItemPositionCenter);
@@ skipping 96 matching lines @@
         m_placeholder = new LayoutFullScreenPlaceholder(this);
         m_placeholder->setStyle(style);
         if (parent()) {
             parent()->addChild(m_placeholder, this);
             parent()->setNeedsLayoutAndPrefWidthsRecalcAndFullPaintInvalidation();
         }
     } else {
         m_placeholder->setStyle(style);
     }
 }