Convert //ios from scoped_ptr to std::unique_ptr.

ios/chrome/browser/history/history_client_impl.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 IOS_CHROME_BROWSER_HISTORY_HISTORY_CLIENT_IMPL_H_
 #define IOS_CHROME_BROWSER_HISTORY_HISTORY_CLIENT_IMPL_H_
 
+#include <memory>
 #include <set>
 
 #include "base/callback_forward.h"
 #include "base/callback_list.h"
 #include "base/macros.h"
-#include "base/memory/scoped_ptr.h"
 #include "components/bookmarks/browser/base_bookmark_model_observer.h"
 #include "components/history/core/browser/history_client.h"
 
 class GURL;
 
 namespace bookmarks {
 class BookmarkModel;
 class BookmarkNode;
 }
 
 class HistoryClientImpl : public history::HistoryClient,
                           public bookmarks::BaseBookmarkModelObserver {
  public:
   explicit HistoryClientImpl(bookmarks::BookmarkModel* bookmark_model);
   ~HistoryClientImpl() override;
 
  private:
   // history::HistoryClient implementation.
   void OnHistoryServiceCreated(
       history::HistoryService* history_service) override;
   void Shutdown() override;
   bool CanAddURL(const GURL& url) override;
   void NotifyProfileError(sql::InitStatus init_status) override;
-  scoped_ptr<history::HistoryBackendClient> CreateBackendClient() override;
+  std::unique_ptr<history::HistoryBackendClient> CreateBackendClient() override;
 
   // bookmarks::BaseBookmarkModelObserver implementation.
   void BookmarkModelChanged() override;
 
   // bookmarks::BookmarkModelObserver implementation.
   void BookmarkNodeRemoved(bookmarks::BookmarkModel* model,
                            const bookmarks::BookmarkNode* parent,
                            int old_index,
                            const bookmarks::BookmarkNode* node,
                            const std::set<GURL>& no_longer_bookmarked) override;
   void BookmarkAllUserNodesRemoved(bookmarks::BookmarkModel* model,
                                    const std::set<GURL>& removed_urls) override;
 
   // BookmarkModel instance providing access to bookmarks. May be null during
   // testing but must outlive HistoryClientImpl if non-null.
   bookmarks::BookmarkModel* bookmark_model_;
   bool is_bookmark_model_observer_;
 
   // Callback invoked when URLs are removed from BookmarkModel.
   base::Callback<void(const std::set<GURL>&)> on_bookmarks_removed_;
 
   // Subscription for notifications of changes to favicons.
-  scoped_ptr<base::CallbackList<void(const std::set<GURL>&,
-                                     const GURL&)>::Subscription>
+  std::unique_ptr<base::CallbackList<void(const std::set<GURL>&,
+                                          const GURL&)>::Subscription>
       favicons_changed_subscription_;
 
   DISALLOW_COPY_AND_ASSIGN(HistoryClientImpl);
 };
 
 #endif  // IOS_CHROME_BROWSER_HISTORY_HISTORY_CLIENT_IMPL_H_