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

Source/core/platform/graphics/GlyphPageTreeNode.cpp

 /*
  * Copyright (C) 2006, 2007, 2008 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
@@ skipping 208 matching lines @@
                 bool zeroFilled = false;
                 RefPtr<GlyphPage> scratchPage;
                 GlyphPage* pageToFill = m_page.get();
                 for (unsigned i = 0; i < numRanges; i++) {
                     const FontDataRange& range = segmentedFontData->rangeAt(i);
                     // all this casting is to ensure all the parameters to min and max have the same type,
                     // to avoid ambiguous template parameter errors on Windows
                     int from = max(0, static_cast<int>(range.from()) - static_cast<int>(start));
                     int to = 1 + min(static_cast<int>(range.to()) - static_cast<int>(start), static_cast<int>(GlyphPage::size) - 1);
                     if (from < static_cast<int>(GlyphPage::size) && to > 0) {
+                        // If this is a custom font needs to be loaded, kick off
+                        // the load here, and do not fill the page so that
+                        // font fallback is used while loading.
+                        if (range.fontData()->isLoadingFallback()) {
+                            range.fontData()->beginLoadIfNeeded();
+                            continue;
+                        }
+
                         if (haveGlyphs && !scratchPage) {
                             scratchPage = GlyphPage::createForMixedFontData(this);
                             pageToFill = scratchPage.get();
                         }
 
                         if (!zeroFilled) {
                             if (from > 0 || to < static_cast<int>(GlyphPage::size)) {
                                 for (unsigned i = 0; i < GlyphPage::size; i++)
                                     pageToFill->setGlyphDataForIndex(i, 0, 0);
                             }
@@ skipping 181 matching lines @@
         printf("\nPage %d:\n", it->key);
         showGlyphPageTree(it->key);
     }
 }
 
 void showGlyphPageTree(unsigned pageNumber)
 {
     WebCore::GlyphPageTreeNode::getRoot(pageNumber)->showSubtree();
 }
 #endif