libtxt: fix reference counting of SkFontStyleSets held by font asset providers

lib/ui/text/asset_manager_font_provider.cc

@@ -44,7 +44,8 @@ SkFontStyleSet* AssetManagerFontProvider::MatchFamily(
   if (found == registered_families_.end()) {
     return nullptr;
   }
-  return SkRef(&found->second);
+  sk_sp<SkFontStyleSet> font_style_set = found->second;
+  return font_style_set.release();
 }
 
 void AssetManagerFontProvider::RegisterAsset(std::string family_name,
@@ -54,14 +55,12 @@ void AssetManagerFontProvider::RegisterAsset(std::string family_name,
 
   if (family_it == registered_families_.end()) {
     family_names_.push_back(family_name);
-    family_it = registered_families_
-                    .emplace(std::piecewise_construct,
-                             std::forward_as_tuple(canonical_name),
-                             std::forward_as_tuple(asset_manager_))
-                    .first;
+    auto value = std::make_pair(
+        canonical_name, sk_make_sp<AssetManagerFontStyleSet>(asset_manager_));
+    family_it = registered_families_.emplace(value).first;
   }
 
-  family_it->second.registerAsset(asset);
+  family_it->second->registerAsset(asset);
 }
 
 AssetManagerFontStyleSet::AssetManagerFontStyleSet(

lib/ui/text/asset_manager_font_provider.h

@@ -75,7 +75,7 @@ class AssetManagerFontProvider : public txt::FontAssetProvider {
 
  private:
   std::shared_ptr<AssetManager> asset_manager_;
-  std::unordered_map<std::string, AssetManagerFontStyleSet>
+  std::unordered_map<std::string, sk_sp<AssetManagerFontStyleSet>>
       registered_families_;
   std::vector<std::string> family_names_;
 

third_party/txt/src/txt/typeface_font_asset_provider.cc

@@ -43,7 +43,8 @@ SkFontStyleSet* TypefaceFontAssetProvider::MatchFamily(
   if (found == registered_families_.end()) {
     return nullptr;
   }
-  return SkRef(&found->second);
+  sk_sp<TypefaceFontStyleSet> font_style_set = found->second;
+  return font_style_set.release();
 }
 
 void TypefaceFontAssetProvider::RegisterTypeface(sk_sp<SkTypeface> typeface) {
@@ -69,13 +70,11 @@ void TypefaceFontAssetProvider::RegisterTypeface(
   auto family_it = registered_families_.find(canonical_name);
   if (family_it == registered_families_.end()) {
     family_names_.push_back(family_name_alias);
-    family_it = registered_families_
-                    .emplace(std::piecewise_construct,
-                             std::forward_as_tuple(canonical_name),
-                             std::forward_as_tuple())
-                    .first;
+    auto value =
+        std::make_pair(canonical_name, sk_make_sp<TypefaceFontStyleSet>());
+    family_it = registered_families_.emplace(value).first;
   }
-  family_it->second.registerTypeface(std::move(typeface));
+  family_it->second->registerTypeface(std::move(typeface));
 }
 
 TypefaceFontStyleSet::TypefaceFontStyleSet() = default;

third_party/txt/src/txt/typeface_font_asset_provider.h

@@ -73,7 +73,8 @@ class TypefaceFontAssetProvider : public FontAssetProvider {
   SkFontStyleSet* MatchFamily(const std::string& family_name) override;
 
  private:
-  std::unordered_map<std::string, TypefaceFontStyleSet> registered_families_;
+  std::unordered_map<std::string, sk_sp<TypefaceFontStyleSet>>
+      registered_families_;
   std::vector<std::string> family_names_;
 
   FML_DISALLOW_COPY_AND_ASSIGN(TypefaceFontAssetProvider);