4 files changed, 19 insertions, 18 deletions
diff --git a/src/common/String.cpp b/src/common/String.cpp
index 8b53b16b..743a33fd 100644
--- a/src/common/String.cpp
+++ b/src/common/String.cpp
@@ -376,4 +376,17 @@ StringView StringView::substr(Index pos, Index size) {
   return StringView(ptr_ + pos, std::min(size, size_ - pos));
 }
 
+std::string StringView::ToUtf8() const { return cru::ToUtf8(ptr_, size_); }
+
+String ToLower(StringView s) {
+  String result;
+  for (auto c : s) result.push_back(ToLower(c));
+  return result;
+}
+
+String ToUpper(StringView s) {
+  String result;
+  for (auto c : s) result.push_back(ToUpper(c));
+  return result;
+}
 }  // namespace cru
diff --git a/src/common/StringUtil.cpp b/src/common/StringUtil.cpp
index 850524b5..c828fa21 100644
--- a/src/common/StringUtil.cpp
+++ b/src/common/StringUtil.cpp
@@ -252,16 +252,4 @@ char16_t ToUpper(char16_t c) {
   }
   return c;
 }
-
-std::u16string ToLower(std::u16string_view s) {
-  std::u16string result;
-  for (auto c : s) result.push_back(ToLower(c));
-  return result;
-}
-
-std::u16string ToUpper(std::u16string_view s) {
-  std::u16string result;
-  for (auto c : s) result.push_back(ToUpper(c));
-  return result;
-}
 }  // namespace cru
diff --git a/src/ui/ThemeManager.cpp b/src/ui/ThemeManager.cpp
index 4a0e08a5..a5280d40 100644
--- a/src/ui/ThemeManager.cpp
+++ b/src/ui/ThemeManager.cpp
@@ -36,15 +36,15 @@ void ThemeManager::Init() {
 }
 
 gsl::not_null<std::shared_ptr<platform::graphics::IBrush>>
-ThemeManager::GetBrush(std::u16string key) {
-  std::u16string k = ToLower(key);
+ThemeManager::GetBrush(StringView key) {
+  String k = ToLower(key);
   auto cached_brush_iter = brushes_.find(k);
   if (cached_brush_iter != brushes_.cend()) {
     return cached_brush_iter->second;
   }
 
   auto color_string =
-      String::FromUtf8(theme_tree_.get<std::string>(ToUtf8(key)));
+      String::FromUtf8(theme_tree_.get<std::string>(key.ToUtf8()));
   auto color = Color::Parse(color_string);
   if (!color) throw BadThemeResourceException("Value is not a valid color.");
   std::shared_ptr<platform::graphics::IBrush> brush =
diff --git a/src/ui/render/ScrollBar.cpp b/src/ui/render/ScrollBar.cpp
index 0d644a1f..aeecd9e2 100644
--- a/src/ui/render/ScrollBar.cpp
+++ b/src/ui/render/ScrollBar.cpp
@@ -39,9 +39,9 @@ constexpr std::array<ScrollBarAreaKind, 5> kScrollBarAreaKindList{
     ScrollBarAreaKind::UpSlot, ScrollBarAreaKind::DownSlot,
     ScrollBarAreaKind::Thumb};
 
-std::u16string GenerateScrollBarThemeColorKey(ScrollBarBrushUsageKind usage,
-                                              ScrollBarBrushStateKind state) {
-  std::u16string result = u"scrollbar.";
+String GenerateScrollBarThemeColorKey(ScrollBarBrushUsageKind usage,
+                                      ScrollBarBrushStateKind state) {
+  String result = u"scrollbar.";
   switch (usage) {
     case ScrollBarBrushUsageKind::Arrow:
       result.append(u"arrow");