Enable "system-ui" generic font family

third_party/WebKit/Source/platform/fonts/FontCache.cpp

 /*
  * Copyright (C) 2006, 2008 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Nicholas Shanks <webkit@nickshanks.com>
  *
  * 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.
@@ skipping 80 matching lines @@
 bool FontCache::s_lcdTextEnabled = false;
 float FontCache::s_deviceScaleFactor = 1.0;
 bool FontCache::s_useSkiaFontFallback = false;
 #endif  // OS(WIN)
 
 FontCache* FontCache::fontCache() {
   DEFINE_STATIC_LOCAL(FontCache, globalFontCache, ());
   return &globalFontCache;
 }
 
+static bool isSystemFontFamily(const FontFaceCreationParams& creationParams) {
+#if OS(MACOSX)
+  return creationParams.creationType() == CreateFontByFamily &&
+         (creationParams.family() == FontFamilyNames::system_ui ||
+          creationParams.family() == FontCache::legacySystemFontFamily());
+#else
+  return creationParams.creationType() == CreateFontByFamily &&
+         creationParams.family() == FontFamilyNames::system_ui;
+#endif
+}
+
 FontPlatformData* FontCache::getFontPlatformData(
     const FontDescription& fontDescription,
-    const FontFaceCreationParams& creationParams,
+    const FontFaceCreationParams& originalCreationParams,
     bool checkingAlternateName) {
   if (!gFontPlatformDataCache) {
     gFontPlatformDataCache = new FontPlatformDataCache;
     platformInit();
   }
 
   float size = fontDescription.effectiveFontSize();
+  const FontFaceCreationParams& creationParams =
+      isSystemFontFamily(originalCreationParams)
+          ? FontFaceCreationParams(systemFontFamily(size))
+          : originalCreationParams;
   unsigned roundedSize = size * FontCacheKey::precisionMultiplier();
   FontCacheKey key = fontDescription.cacheKey(creationParams);
 
   // Remove the font size from the cache key, and handle the font size
   // separately in the inner HashMap. So that different size of FontPlatformData
   // can share underlying SkTypeface.
   if (RuntimeEnabledFeatures::fontCacheScalingEnabled())
     key.clearFontSize();
 
   FontPlatformData* result;
@@ skipping 143 matching lines @@
 #if ENABLE(ASSERT)
   if (shouldRetain == DoNotRetain)
     ASSERT(m_purgePreventCount);
 #endif
 
   return gFontDataCache->get(platformData, shouldRetain);
 }
 
 bool FontCache::isPlatformFontAvailable(const FontDescription& fontDescription,
                                         const AtomicString& family) {
+  if (family == FontFamilyNames::system_ui)
+    return true;
+#if OS(MACOSX)
+  if (family == FontCache::legacySystemFontFamily())
+    return true;
+#endif
   bool checkingAlternateName = true;
   return getFontPlatformData(
       fontDescription,
       FontFaceCreationParams(adjustFamilyNameToAvoidUnsupportedFonts(family)),
       checkingAlternateName);
 }
 
 SimpleFontData* FontCache::getNonRetainedLastResortFallbackFont(
     const FontDescription& fontDescription) {
   return getLastResortFallbackFont(fontDescription, DoNotRetain).leakRef();
@@ skipping 165 matching lines @@
   for (iter = gFallbackListShaperCache->begin();
        iter != gFallbackListShaperCache->end(); ++iter) {
     shapeResultCacheSize += iter->value->byteSize();
   }
   dump->AddScalar("size", "bytes", shapeResultCacheSize);
   memoryDump->AddSuballocation(dump->guid(),
                                WTF::Partitions::kAllocatedObjectPoolName);
 }
 
 }  // namespace blink