Pass InteractionStats by value

chrome/browser/password_manager/password_store_proxy_mac.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_PASSWORD_MANAGER_PASSWORD_STORE_PROXY_MAC_H_
 #define CHROME_BROWSER_PASSWORD_MANAGER_PASSWORD_STORE_PROXY_MAC_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 82 matching lines @@
       base::Time delete_end) override;
   std::vector<std::unique_ptr<autofill::PasswordForm>> FillMatchingLogins(
       const FormDigest& form) override;
   bool FillAutofillableLogins(
       std::vector<std::unique_ptr<autofill::PasswordForm>>* forms) override;
   bool FillBlacklistLogins(
       std::vector<std::unique_ptr<autofill::PasswordForm>>* forms) override;
   void AddSiteStatsImpl(
       const password_manager::InteractionsStats& stats) override;
   void RemoveSiteStatsImpl(const GURL& origin_domain) override;
-  std::vector<std::unique_ptr<password_manager::InteractionsStats>>
-  GetSiteStatsImpl(const GURL& origin_domain) override;
+  std::vector<password_manager::InteractionsStats> GetSiteStatsImpl(
+      const GURL& origin_domain) override;
 
   scoped_refptr<SimplePasswordStoreMac> password_store_simple_;
 
   // The login metadata SQL database. If opening the DB on |thread_| fails,
   // |login_metadata_db_| will be reset to NULL for the lifetime of |this|.
   // The ownership may be transferred to |password_store_simple_|.
   std::unique_ptr<password_manager::LoginDatabase> login_metadata_db_;
 
   // Keychain wrapper.
   const std::unique_ptr<crypto::AppleKeychain> keychain_;
 
   // Thread that the synchronous methods are run on.
   std::unique_ptr<base::Thread> thread_;
 
   // Current migration status for the profile.
   IntegerPrefMember migration_status_;
 
   // List of tasks filled by InitOnBackgroundThread. They can't be just posted
   // to the UI thread because the message loop can shut down before executing
   // them. If this is the case then Shutdown() flushes the tasks after stopping
   // the background thread.
   // After InitOnBackgroundThread is run once, the queue may not be modified on
   // the background thread any more.
   std::vector<base::Closure> pending_ui_tasks_;
 
   DISALLOW_COPY_AND_ASSIGN(PasswordStoreProxyMac);
 };
 
 #endif  // CHROME_BROWSER_PASSWORD_MANAGER_PASSWORD_STORE_PROXY_MAC_H_