Only FontCache should know about system font substitution

Source/platform/fonts/FontCache.cpp

Index: Source/platform/fonts/FontCache.cpp
diff --git a/Source/platform/fonts/FontCache.cpp b/Source/platform/fonts/FontCache.cpp
index e54e0d8dc25e491a130cbd23b9d5c9efaa6817f8..eaafdf6c03cb40e2861530d25cb80ffd6ff003df 100644
--- a/Source/platform/fonts/FontCache.cpp
+++ b/Source/platform/fonts/FontCache.cpp
@@ -170,7 +170,7 @@ PassRefPtr<SimpleFontData> FontCache::fontDataFromFontPlatformData(const FontPla
 bool FontCache::isPlatformFontAvailable(const FontDescription& fontDescription, const AtomicString& family)
 {
     bool checkingAlternateName = true;
-    return getFontPlatformData(fontDescription, family, checkingAlternateName);
+    return getFontPlatformData(fontDescription, adjustFamilyNameToAvoidUnsupportedFonts(family), checkingAlternateName);
 }
 
 SimpleFontData* FontCache::getNonRetainedLastResortFallbackFont(const FontDescription& fontDescription)