Make ContentSuggestionsService recognize new/removed categories

components/ntp_snippets/offline_pages/offline_page_suggestions_provider.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 "components/ntp_snippets/offline_pages/offline_page_suggestions_provider.h"
 
 #include "base/bind.h"
 #include "base/strings/string_number_conversions.h"
 
 using offline_pages::MultipleOfflinePageItemResult;
@@ skipping 110 matching lines @@
     // TODO(pke): Get more reasonable data from the OfflinePageModel here.
     suggestion.set_title(item.url.spec());
     suggestion.set_snippet_text(std::string());
     suggestion.set_publish_date(item.creation_time);
     suggestion.set_publisher_name(item.url.host());
     suggestions.emplace_back(std::move(suggestion));
     if (suggestions.size() == kMaxSuggestionsCount)
       break;
   }
 
-  observer_->OnNewSuggestions(provided_category_, std::move(suggestions));
+  observer_->OnNewSuggestions(this, provided_category_, std::move(suggestions));
 }
 
 void OfflinePageSuggestionsProvider::NotifyStatusChanged(
     CategoryStatus new_status) {
   if (category_status_ == new_status)
     return;
   category_status_ = new_status;
 
   if (!observer_)
     return;
-  observer_->OnCategoryStatusChanged(provided_category_, new_status);
+  observer_->OnCategoryStatusChanged(this, provided_category_, new_status);
 }
 
 }  // namespace ntp_snippets