Use unicode-range to prevent unnecessary @font-face donwnloads

Source/core/css/CSSFontFaceSource.cpp

 /*
  * Copyright (C) 2007, 2008, 2010, 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 50 matching lines @@
     if (m_font)
         m_font->removeClient(this);
     pruneTable();
 }
 
 void CSSFontFaceSource::pruneTable()
 {
     if (m_fontDataTable.isEmpty())
         return;
 
+    for (FontDataTable::iterator it = m_fontDataTable.begin(); it != m_fontDataTable.end(); ++it) {
+        if (SimpleFontData* fontData = it->value.get())
+            fontData->clearCSSFontFaceSource();
+    }
     m_fontDataTable.clear();
 }
 
 bool CSSFontFaceSource::isLocal() const
 {
     if (m_font)
         return false;
 #if ENABLE(SVG_FONTS)
     if (m_svgFontFaceElement)
         return false;
 #endif
     return true;
 }
 
+bool CSSFontFaceSource::isLoading() const
+{
+    if (m_font)
+        return !m_font->stillNeedsLoad() && !m_font->isLoaded();
+    return false;
+}
+
 bool CSSFontFaceSource::isLoaded() const
 {
     if (m_font)
         return m_font->isLoaded();
     return true;
 }
 
 bool CSSFontFaceSource::isValid() const
 {
     if (m_font)
@@ skipping 91 matching lines @@
                     fontDescription.orientation(), fontDescription.widthVariant()), true, false);
             }
         } else {
 #if ENABLE(SVG_FONTS)
             // In-Document SVG Fonts
             if (m_svgFontFaceElement)
                 fontData = SimpleFontData::create(SVGFontData::create(m_svgFontFaceElement.get()), fontDescription.computedPixelSize(), syntheticBold, syntheticItalic);
 #endif
         }
     } else {
-        // Kick off the load. Do it soon rather than now, because we may be in the middle of layout,
-        // and the loader may invoke arbitrary delegate or event handler code.
-        fontSelector->beginLoadingFontSoon(m_font.get());
-
         // This temporary font is not retained and should not be returned.
         FontCachePurgePreventer fontCachePurgePreventer;
         SimpleFontData* temporaryFont = fontCache()->getNonRetainedLastResortFallbackFont(fontDescription);
         fontData = SimpleFontData::create(temporaryFont->platformData(), true, true);
+        fontData->setCSSFontFaceSource(this);
     }
 
     return fontData; // No release, because fontData is a reference to a RefPtr that is held in the m_fontDataTable.
 }
 
 #if ENABLE(SVG_FONTS)
 SVGFontFaceElement* CSSFontFaceSource::svgFontFaceElement() const
 {
     return m_svgFontFaceElement.get();
 }
@@ skipping 33 matching lines @@
         return false;
     return fontCache()->isPlatformFontAvailable(fontDescription, m_string, true);
 }
 
 void CSSFontFaceSource::willUseFontData()
 {
     if (!isLoaded())
         m_histograms.willUseFontData();
 }
 
+void CSSFontFaceSource::beginLoadingFontSoon()
+{
+    ASSERT(m_face);
+    ASSERT(m_font);
+    m_face->beginLoadingFontSoon(m_font.get());
+}
+
 CSSFontFaceSource::FontLoadHistograms::~FontLoadHistograms()
 {
     if (m_styledTime > 0)
         HistogramSupport::histogramEnumeration("WebFont.UsageType", StyledButNotUsed, UsageTypeMax);
 }
 
 void CSSFontFaceSource::FontLoadHistograms::willUseFontData()
 {
     if (!m_styledTime)
         m_styledTime = currentTimeMS();
@@ skipping 44 matching lines @@
     if (size < 50 * 1024)
         return "WebFont.DownloadTime.1.10KBTo50KB";
     if (size < 100 * 1024)
         return "WebFont.DownloadTime.2.50KBTo100KB";
     if (size < 1024 * 1024)
         return "WebFont.DownloadTime.3.100KBTo1MB";
     return "WebFont.DownloadTime.4.Over1MB";
 }
 
 }