Collect active stylesheets and and apply asynchronously.

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 292 matching lines @@
                                 ExceptionState&) const {
   ASSERT(fontFace);
   if (!inActiveDocumentContext())
     return false;
   return m_nonCSSConnectedFaces.contains(fontFace) ||
          isCSSConnectedFontFace(fontFace);
 }
 
 const HeapListHashSet<Member<FontFace>>& FontFaceSet::cssConnectedFontFaceList()
     const {
-  Document* d = document();
-  d->ensureStyleResolver();  // Flush pending style changes.
-  return d->styleEngine()
+  Document* document = this->document();
+  document->updateActiveStyle();
+  return document->styleEngine()
       .fontSelector()
       ->fontFaceCache()
       ->cssConnectedFontFaces();
 }
 
 bool FontFaceSet::isCSSConnectedFontFace(FontFace* fontFace) const {
   return cssConnectedFontFaceList().contains(fontFace);
 }
 
 size_t FontFaceSet::size() const {
@@ skipping 134 matching lines @@
 
   FontDescription defaultFontDescription;
   defaultFontDescription.setFamily(fontFamily);
   defaultFontDescription.setSpecifiedSize(defaultFontSize);
   defaultFontDescription.setComputedSize(defaultFontSize);
 
   style->setFontDescription(defaultFontDescription);
 
   style->font().update(style->font().getFontSelector());
 
+  document()->updateActiveStyle();
   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)
     return;
@@ skipping 79 matching lines @@
   visitor->trace(m_failedFonts);
   visitor->trace(m_nonCSSConnectedFaces);
   visitor->trace(m_asyncRunner);
   EventTargetWithInlineData::trace(visitor);
   Supplement<Document>::trace(visitor);
   SuspendableObject::trace(visitor);
   FontFace::LoadFontCallback::trace(visitor);
 }
 
 }  // namespace blink