No need to recalc style before StyleResolver::computeFont.

third_party/WebKit/Source/core/css/FontFaceSet.cpp

 /*
  * Copyright (C) 2013 Google 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 481 matching lines @@
 
     FontDescription defaultFontDescription;
     defaultFontDescription.setFamily(fontFamily);
     defaultFontDescription.setSpecifiedSize(defaultFontSize);
     defaultFontDescription.setComputedSize(defaultFontSize);
 
     style->setFontDescription(defaultFontDescription);
 
     style->font().update(style->font().fontSelector());
 
-    document()->updateLayoutTreeIfNeeded();
     document()->ensureStyleResolver().computeFont(style.get(), *parsedStyle);
 
     font = style->font();
     font.update(document()->styleEngine().fontSelector());
     return true;
 }
 
 void FontFaceSet::FontLoadHistogram::updateStatus(FontFace* fontFace)
 {
     if (m_status == Reported)
@@ skipping 46 matching lines @@
     visitor->trace(m_loadedFonts);
     visitor->trace(m_failedFonts);
     visitor->trace(m_nonCSSConnectedFaces);
     HeapSupplement<Document>::trace(visitor);
 #endif
     EventTargetWithInlineData::trace(visitor);
     ActiveDOMObject::trace(visitor);
 }
 
 } // namespace blink