Unloaded font segment should not affect primaryFontData

Source/platform/fonts/FontFallbackList.cpp

 /*
  * Copyright (C) 2006 Apple Computer, 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 117 matching lines @@
             fontData = fontDataAt(fontDescription, 0);
             if (!fontData)
                 fontData = FontCache::fontCache()->getLastResortFallbackFont(fontDescription).get();
             ASSERT(fontData);
             return fontData;
         }
 
         if (fontData->isSegmented() && !toSegmentedFontData(fontData)->containsCharacter(' '))
             continue;
 
+        const SimpleFontData* simpleFontData = fontData->fontDataForCharacter(' ');
+        ASSERT(simpleFontData);
+
         // When a custom font is loading, we should use the correct fallback font to layout the text.
         // Here skip the temporary font for the loading custom font which may not act as the correct fallback font.
-        if (!fontData->isLoadingFallback())
+        if (!simpleFontData->isLoadingFallback())
             return fontData;
 
         // Begin to load the first custom font if needed.
         if (shouldLoadCustomFont) {
             shouldLoadCustomFont = false;
-            const SimpleFontData* simpleFontData = fontData->fontDataForCharacter(' ');
-            if (simpleFontData && simpleFontData->customFontData())
-                simpleFontData->customFontData()->beginLoadIfNeeded();
+            simpleFontData->customFontData()->beginLoadIfNeeded();
         }
     }
 }
 
 PassRefPtr<FontData> FontFallbackList::getFontData(const FontDescription& fontDescription, int& familyIndex) const
 {
     RefPtr<FontData> result;
 
     int startIndex = familyIndex;
     const FontFamily* startFamily = &fontDescription.family();
@@ skipping 51 matching lines @@
     RefPtr<FontData> result = getFontData(fontDescription, m_familyIndex);
     if (result) {
         m_fontList.append(result);
         if (result->isLoadingFallback())
             m_hasLoadingFallback = true;
     }
     return result.get();
 }
 
 }