[Remote suggestions] Remove the unique_ptr wrapper around callbacks

chrome/browser/ui/webui/snippets_internals_message_handler.cc

 // Copyright 2016 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.
 
 #include "chrome/browser/ui/webui/snippets_internals_message_handler.h"
 
 #include <memory>
 #include <set>
 #include <utility>
 #include <vector>
@@ skipping 296 matching lines @@
     const base::ListValue* args) {
   DCHECK_EQ(0u, args->GetSize());
   content_suggestions_service_->user_classifier()
       ->ClearClassificationForDebugging();
   SendClassification();
 }
 
 void SnippetsInternalsMessageHandler::FetchRemoteSuggestionsInTheBackground(
     const base::ListValue* args) {
   DCHECK_EQ(0u, args->GetSize());
-  remote_suggestions_provider_->RefetchInTheBackground(nullptr);
+  remote_suggestions_provider_->RefetchInTheBackground(
+      RemoteSuggestionsProvider::FetchStatusCallback());
 }
 
 void SnippetsInternalsMessageHandler::SendAllContent() {
   SendBoolean(
       "flag-article-suggestions",
       base::FeatureList::IsEnabled(ntp_snippets::kArticleSuggestionsFeature));
   SendBoolean("flag-recent-offline-tab-suggestions",
               base::FeatureList::IsEnabled(
                   ntp_snippets::kRecentOfflineTabSuggestionsFeature));
   SendBoolean("flag-offlining-recent-pages-feature",
@@ skipping 126 matching lines @@
 void SnippetsInternalsMessageHandler::OnDismissedSuggestionsLoaded(
     Category category,
     std::vector<ContentSuggestion> dismissed_suggestions) {
   if (dismissed_state_[category] == DismissedState::HIDDEN) {
     return;
   }
   dismissed_suggestions_[category] = std::move(dismissed_suggestions);
   dismissed_state_[category] = DismissedState::VISIBLE;
   SendContentSuggestions();
 }