Make HarfBuzzFace release SimpleFontData.

third_party/WebKit/Source/platform/fonts/shaping/HarfBuzzFace.cpp

 /*
  * Copyright (c) 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.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 111 matching lines @@
     HarfBuzzFontCache;
 
 static HarfBuzzFontCache* harfBuzzFontCache() {
   DEFINE_STATIC_LOCAL(HarfBuzzFontCache, s_harfBuzzFontCache, ());
   return &s_harfBuzzFontCache;
 }
 
 static PassRefPtr<HbFontCacheEntry> createHbFontCacheEntry(hb_face_t*);
 
 HarfBuzzFace::HarfBuzzFace(FontPlatformData* platformData, uint64_t uniqueID)
-    : m_platformData(platformData), m_uniqueID(uniqueID) {
+    : m_platformData(platformData),
+      m_uniqueID(uniqueID),
+      m_simpleFontData(nullptr) {
   HarfBuzzFontCache::AddResult result =
       harfBuzzFontCache()->add(m_uniqueID, nullptr);
   if (result.isNewEntry) {
     HbFaceUniquePtr face(createFace());
     result.storedValue->value = createHbFontCacheEntry(face.get());
   }
   result.storedValue->value->ref();
   m_unscaledFont = result.storedValue->value->hbFont();
   m_harfBuzzFontData = result.storedValue->value->hbFontData();
 }
 
 HarfBuzzFace::~HarfBuzzFace() {
   HarfBuzzFontCache::iterator result = harfBuzzFontCache()->find(m_uniqueID);
   ASSERT_WITH_SECURITY_IMPLICATION(result != harfBuzzFontCache()->end());
   ASSERT(result.get()->value->refCount() > 1);
   result.get()->value->deref();
   if (result.get()->value->refCount() == 1)
     harfBuzzFontCache()->remove(m_uniqueID);
+  if (m_simpleFontData)
+    FontCache::fontCache()->releaseFontData(m_simpleFontData);

[drott, 2016/10/11 11:40:44]

Yes, this definitely seems needed.

 }
 
 static hb_position_t SkiaScalarToHarfBuzzPosition(SkScalar value) {
   // We treat HarfBuzz hb_position_t as 16.16 fixed-point.
   static const int kHbPosition1 = 1 << 16;
   return clampTo<int>(value * kHbPosition1);
 }
 
 static hb_bool_t harfBuzzGetGlyph(hb_font_t* hbFont,
                                   void* fontData,
@@ skipping 202 matching lines @@
   hb_font_set_funcs(unscaledFont, harfBuzzSkiaGetFontFuncs(),
                     cacheEntry->hbFontData(), nullptr);
   return cacheEntry;
 }
 
 hb_font_t* HarfBuzzFace::getScaledFont(
     PassRefPtr<UnicodeRangeSet> rangeSet) const {
   m_platformData->setupPaint(&m_harfBuzzFontData->m_paint);
   m_harfBuzzFontData->m_paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
   m_harfBuzzFontData->m_rangeSet = rangeSet;
-  m_harfBuzzFontData->m_simpleFontData =
-      FontCache::fontCache()
-          ->fontDataFromFontPlatformData(m_platformData)
-          .get();
+  if (!m_simpleFontData) {
+    m_simpleFontData = FontCache::fontCache()
+                           ->fontDataFromFontPlatformData(m_platformData)
+                           .get();
+  }
+  DCHECK_EQ(m_simpleFontData,
+            FontCache::fontCache()
+                ->fontDataFromFontPlatformData(m_platformData, DoNotRetain)
+                .get());
+  m_harfBuzzFontData->m_simpleFontData = m_simpleFontData;
   ASSERT(m_harfBuzzFontData->m_simpleFontData);
   int scale = SkiaScalarToHarfBuzzPosition(m_platformData->size());
   hb_font_set_scale(m_unscaledFont, scale, scale);
   return m_unscaledFont;
 }
 
 }  // namespace blink