Remove raw base::DictionaryValue::Set

ios/chrome/browser/autofill/autofill_agent.mm

Index: ios/chrome/browser/autofill/autofill_agent.mm
diff --git a/ios/chrome/browser/autofill/autofill_agent.mm b/ios/chrome/browser/autofill/autofill_agent.mm
index 9f2e38ce68b885379cc81e1059b2ea4c521dd6d8..39435727925f35d7f6255f15a1c12068e3ba2825 100644
--- a/ios/chrome/browser/autofill/autofill_agent.mm
+++ b/ios/chrome/browser/autofill/autofill_agent.mm
@@ -810,14 +810,14 @@ void GetFormAndField(autofill::FormData* form,
   formData->SetString("formName", base::UTF16ToUTF8(form.name));
   // Note: Destruction of all child base::Value types is handled by the root
   // formData object on its own destruction.
-  base::DictionaryValue* fieldsData = new base::DictionaryValue;
+  auto fieldsData = base::MakeUnique<base::DictionaryValue>();
 
   const std::vector<autofill::FormFieldData>& fields = form.fields;
   for (const auto& fieldData : fields) {
     fieldsData->SetStringWithoutPathExpansion(base::UTF16ToUTF8(fieldData.name),
                                               fieldData.value);
   }
-  formData->Set("fields", fieldsData);
+  formData->Set("fields", std::move(fieldsData));
 
   // Stringify the JSON data and send it to the UIWebView-side fillForm method.
   std::string dataString;