Make ContentSuggestionsService recognize new/removed categories

components/ntp_snippets/ntp_snippets_service.cc

 // 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.
 
 #include "components/ntp_snippets/ntp_snippets_service.h"
 
 #include <algorithm>
 #include <iterator>
 #include <utility>
 
@@ skipping 777 matching lines @@
         MakeUniqueID(provided_category_, snippet->id()),
         snippet->best_source().url);
     suggestion.set_amp_url(snippet->best_source().amp_url);
     suggestion.set_title(snippet->title());
     suggestion.set_snippet_text(snippet->snippet());
     suggestion.set_publish_date(snippet->publish_date());
     suggestion.set_publisher_name(snippet->best_source().publisher_name);
     suggestion.set_score(snippet->score());
     result.emplace_back(std::move(suggestion));
   }
-  observer_->OnNewSuggestions(provided_category_, std::move(result));
+  observer_->OnNewSuggestions(this, provided_category_, std::move(result));
 }
 
 void NTPSnippetsService::NotifyCategoryStatusChanged() {
   if (observer_) {
-    observer_->OnCategoryStatusChanged(provided_category_, category_status_);
+    observer_->OnCategoryStatusChanged(this, provided_category_,
+                                       category_status_);
   }
 }
 
 }  // namespace ntp_snippets