perf: avoid unnecessary base value clone (#38537)

shell/browser/electron_browser_context.cc

@@ -329,10 +329,8 @@ void ElectronBrowserContext::InitPrefs() {
 #endif
 
 #if BUILDFLAG(ENABLE_BUILTIN_SPELLCHECKER)
-  base::Value::List current_dictionaries =
-      prefs()->GetList(spellcheck::prefs::kSpellCheckDictionaries).Clone();
   // No configured dictionaries, the default will be en-US
-  if (current_dictionaries.empty()) {
+  if (prefs()->GetList(spellcheck::prefs::kSpellCheckDictionaries).empty()) {
     std::string default_code = spellcheck::GetCorrespondingSpellCheckLanguage(
         base::i18n::GetConfiguredLocale());
     if (!default_code.empty()) {

shell/browser/mac/dict_util.mm

@@ -14,7 +14,7 @@ namespace electron {
 
 NSArray* ListValueToNSArray(const base::Value::List& value) {
   std::string json;
-  if (!base::JSONWriter::Write(base::Value(value.Clone()), &json))
+  if (!base::JSONWriter::Write(base::ValueView{value}, &json))
     return nil;
   NSData* jsonData = [NSData dataWithBytes:json.c_str() length:json.length()];
   id obj = [NSJSONSerialization JSONObjectWithData:jsonData
@@ -57,7 +57,7 @@ base::Value::List NSArrayToValue(NSArray* arr) {
 
 NSDictionary* DictionaryValueToNSDictionary(const base::Value::Dict& value) {
   std::string json;
-  if (!base::JSONWriter::Write(base::Value(value.Clone()), &json))
+  if (!base::JSONWriter::Write(base::ValueView{value}, &json))
     return nil;
   NSData* jsonData = [NSData dataWithBytes:json.c_str() length:json.length()];
   id obj = [NSJSONSerialization JSONObjectWithData:jsonData

shell/browser/usb/usb_chooser_context.cc

@@ -206,7 +206,7 @@ void UsbChooserContext::RevokeObjectPermissionInternal(
     v8::HandleScope scope(isolate);
     gin_helper::Dictionary details =
         gin_helper::Dictionary::CreateEmpty(isolate);
-    details.Set("device", object.Clone());
+    details.Set("device", object);
     details.Set("origin", origin.Serialize());
     session->Emit("usb-device-revoked", details);
   }

shell/common/gin_converters/extension_converter.cc

@@ -22,7 +22,7 @@ v8::Local<v8::Value> Converter<const extensions::Extension*>::ToV8(
   dict.Set("path", extension->path());
   dict.Set("url", extension->url());
   dict.Set("version", extension->VersionString());
-  dict.Set("manifest", extension->manifest()->value()->Clone());
+  dict.Set("manifest", *extension->manifest()->value());
 
   return gin::ConvertToV8(isolate, dict);
 }

shell/common/gin_converters/value_converter.cc

@@ -25,14 +25,6 @@ bool Converter<base::Value::Dict>::FromV8(v8::Isolate* isolate,
   }
 }
 
-v8::Local<v8::Value> Converter<base::Value::Dict>::ToV8(
-    v8::Isolate* isolate,
-    const base::Value::Dict& val) {
-  base::Value value(val.Clone());
-  return content::V8ValueConverter::Create()->ToV8Value(
-      value, isolate->GetCurrentContext());
-}
-
 bool Converter<base::Value>::FromV8(v8::Isolate* isolate,
                                     v8::Local<v8::Value> val,
                                     base::Value* out) {
@@ -47,8 +39,9 @@ bool Converter<base::Value>::FromV8(v8::Isolate* isolate,
   }
 }
 
-v8::Local<v8::Value> Converter<base::Value>::ToV8(v8::Isolate* isolate,
+v8::Local<v8::Value> Converter<base::ValueView>::ToV8(
-                                                  const base::Value& val) {
+    v8::Isolate* isolate,
+    const base::ValueView val) {
   return content::V8ValueConverter::Create()->ToV8Value(
       val, isolate->GetCurrentContext());
 }
@@ -67,12 +60,4 @@ bool Converter<base::Value::List>::FromV8(v8::Isolate* isolate,
   }
 }
 
-v8::Local<v8::Value> Converter<base::Value::List>::ToV8(
-    v8::Isolate* isolate,
-    const base::Value::List& val) {
-  base::Value value(val.Clone());
-  return content::V8ValueConverter::Create()->ToV8Value(
-      value, isolate->GetCurrentContext());
-}
-
 }  // namespace gin

shell/common/gin_converters/value_converter.h

@@ -10,13 +10,21 @@
 
 namespace gin {
 
+template <>
+struct Converter<base::ValueView> {
+  static v8::Local<v8::Value> ToV8(v8::Isolate* isolate,
+                                   const base::ValueView val);
+};
+
 template <>
 struct Converter<base::Value::Dict> {
   static bool FromV8(v8::Isolate* isolate,
                      v8::Local<v8::Value> val,
                      base::Value::Dict* out);
   static v8::Local<v8::Value> ToV8(v8::Isolate* isolate,
-                                   const base::Value::Dict& val);
+                                   const base::Value::Dict& val) {
+    return gin::ConvertToV8(isolate, base::ValueView{val});
+  }
 };
 
 template <>
@@ -25,7 +33,9 @@ struct Converter<base::Value> {
                      v8::Local<v8::Value> val,
                      base::Value* out);
   static v8::Local<v8::Value> ToV8(v8::Isolate* isolate,
-                                   const base::Value& val);
+                                   const base::Value& val) {
+    return gin::ConvertToV8(isolate, base::ValueView{val});
+  }
 };
 
 template <>
@@ -34,7 +44,9 @@ struct Converter<base::Value::List> {
                      v8::Local<v8::Value> val,
                      base::Value::List* out);
   static v8::Local<v8::Value> ToV8(v8::Isolate* isolate,
-                                   const base::Value::List& val);
+                                   const base::Value::List& val) {
+    return gin::ConvertToV8(isolate, base::ValueView{val});
+  }
 };
 
 }  // namespace gin