Initiate webfont download right after style recalc

Source/core/css/CSSFontFace.cpp

 /*
  * Copyright (C) 2007, 2008, 2011 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 66 matching lines @@
     fontSelector->beginLoadingFontSoon(resource);
 
     if (loadStatus() == FontFace::Unloaded)
         setLoadStatus(FontFace::Loading);
 }
 
 void CSSFontFace::fontLoaded(CSSFontFaceSource* source)
 {
     if (source != m_activeSource)
         return;
+    m_activeSource = 0;
 
     // FIXME: Can we assert that m_segmentedFontFace is non-null? That may
     // require stopping in-progress font loading when the last
     // CSSSegmentedFontFace is removed.
     if (!m_segmentedFontFace)
         return;
 
     CSSFontSelector* fontSelector = m_segmentedFontFace->fontSelector();
     fontSelector->fontLoaded();
 
@@ skipping 33 matching lines @@
 
     if (loadStatus() == FontFace::Unloaded)
         setLoadStatus(FontFace::Loading);
     if (loadStatus() == FontFace::Loading)
         setLoadStatus(FontFace::Error);
     return 0;
 }
 
 void CSSFontFace::willUseFontData(const FontDescription& fontDescription)
 {
-    if (loadStatus() != FontFace::Unloaded)
+    if (loadStatus() != FontFace::Unloaded || m_activeSource)
+        return;
+
+    // Kicks off font load here only if the @font-face has no unicode-range.
+    // @font-faces with unicode-range will be loaded when a GlyphPage for the
+    // font is created.
+    // FIXME: Pass around the text to render from RenderText, and kick download
+    // if m_ranges intersects with the text. Make sure this does not cause
+    // performance regression.
+    if (!m_ranges.isEntireRange())
         return;
 
     ASSERT(m_segmentedFontFace);
 
     size_t size = m_sources.size();
     for (size_t i = 0; i < size; ++i) {
         if (!m_sources[i]->isValid() || (m_sources[i]->isLocal() && !m_sources[i]->isLocalFontAvailable(fontDescription)))
             continue;
-        if (!m_sources[i]->isLocal())
+        if (!m_sources[i]->isLocal()) {
+            m_activeSource = m_sources[i].get();
             m_sources[i]->willUseFontData();
+        }
         break;
     }
 }
 
 void CSSFontFace::setLoadStatus(FontFace::LoadStatus newStatus)
 {
     ASSERT(m_fontFace);
     m_fontFace->setLoadStatus(newStatus);
 
     Document* document = m_segmentedFontFace->fontSelector()->document();
@@ skipping 12 matching lines @@
         break;
     default:
         break;
     }
 }
 
 bool CSSFontFace::UnicodeRangeSet::intersectsWith(const String& text) const
 {
     if (text.isEmpty())
         return false;
-    if (m_ranges.isEmpty())
-        return true; // Empty UnicodeRangeSet represents the whole code space.
+    if (isEntireRange())
+        return true;
 
     // FIXME: This takes O(text.length() * m_ranges.size()) time. It would be
     // better to make m_ranges sorted and use binary search.
     unsigned index = 0;
     while (index < text.length()) {
         UChar32 c = text.characterStartingAt(index);
         index += U16_LENGTH(c);
         for (unsigned i = 0; i < m_ranges.size(); i++) {
             if (m_ranges[i].contains(c))
                 return true;
         }
     }
     return false;
 }
 
 }