Enable "system-ui" generic font family

third_party/WebKit/Source/platform/fonts/win/FontCacheSkiaWin.cpp

 /*
  * Copyright (C) 2006, 2007 Apple Computer, Inc.
  * Copyright (c) 2006, 2007, 2008, 2009, 2012 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 58 matching lines @@
 // static
 void FontCache::addSideloadedFontForTesting(SkTypeface* typeface) {
   if (!s_sideloadedFonts)
     s_sideloadedFonts = new HashMap<String, sk_sp<SkTypeface>>;
   SkString name;
   typeface->getFamilyName(&name);
   s_sideloadedFonts->set(name.c_str(), sk_sp<SkTypeface>(typeface));
 }
 
 // static
+const AtomicString& FontCache::systemFontFamily(float) {
+  return menuFontFamily();
+}
+
+// static
 void FontCache::setMenuFontMetrics(const wchar_t* familyName,
                                    int32_t fontHeight) {
   s_menuFontFamilyName = new AtomicString(familyName);
   s_menuFontHeight = ensureMinimumFontHeightIfNeeded(fontHeight);
 }
 
 // static
 void FontCache::setSmallCaptionFontMetrics(const wchar_t* familyName,
                                            int32_t fontHeight) {
   s_smallCaptionFontFamilyName = new AtomicString(familyName);
@@ skipping 319 matching lines @@
     if (typefacesMatchesFamily(tf.get(), family)) {
       result->setMinSizeForSubpixel(minSizeForSubpixelForFont);
       break;
     }
   }
 
   return result;
 }
 
 }  // namespace blink