Enable "system-ui" generic font family

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

Index: third_party/WebKit/Source/platform/fonts/win/FontCacheSkiaWin.cpp
diff --git a/third_party/WebKit/Source/platform/fonts/win/FontCacheSkiaWin.cpp b/third_party/WebKit/Source/platform/fonts/win/FontCacheSkiaWin.cpp
index f29a489bd0eb85e6bf2b5296e4d59d677e83c6a1..979513d9a6aa6d06295b5b0b548bb764c4e043aa 100644
--- a/third_party/WebKit/Source/platform/fonts/win/FontCacheSkiaWin.cpp
+++ b/third_party/WebKit/Source/platform/fonts/win/FontCacheSkiaWin.cpp
@@ -76,6 +76,11 @@ void FontCache::addSideloadedFontForTesting(SkTypeface* typeface) {
 }
 
 // static
+const AtomicString& FontCache::systemFontFamily() {
+  return menuFontFamily();
+}
+
+// static
 void FontCache::setMenuFontMetrics(const wchar_t* familyName,
                                    int32_t fontHeight) {
   s_menuFontFamilyName = new AtomicString(familyName);