Remove deleted offline page suggestions from opened NTPs

components/ntp_snippets/content_suggestions_service.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/content_suggestions_service.h"
 
 #include <algorithm>
 #include <iterator>
 
 #include "base/bind.h"
@@ skipping 117 matching lines @@
   }
   Category category = id_category_map_.at(suggestion_id);
   if (!providers_by_category_.count(category)) {
     LOG(WARNING) << "Dismissed suggestion " << suggestion_id
                  << " for unavailable category " << category;
     return;
   }
   providers_by_category_[category]->DismissSuggestion(suggestion_id);
 
   // Remove the suggestion locally.
-  id_category_map_.erase(suggestion_id);
-  std::vector<ContentSuggestion>* suggestions =
-      &suggestions_by_category_[category];
-  auto position =
-      std::find_if(suggestions->begin(), suggestions->end(),
-                   [&suggestion_id](const ContentSuggestion& suggestion) {
-                     return suggestion_id == suggestion.id();
-                   });
-  DCHECK(position != suggestions->end())
-      << "The dismissed suggestion " << suggestion_id
-      << " has already been removed. Providers must not call OnNewSuggestions"
-         " in response to DismissSuggestion.";
-  suggestions->erase(position);
+  bool removed = RemoveSuggestionByID(category, suggestion_id);
+  DCHECK(removed) << "The dismissed suggestion " << suggestion_id
+                  << " has already been removed. Providers must not call"
+                  << " OnNewSuggestions in response to DismissSuggestion.";
 }
 
 void ContentSuggestionsService::AddObserver(Observer* observer) {
   observers_.AddObserver(observer);
 }
 
 void ContentSuggestionsService::RemoveObserver(Observer* observer) {
   observers_.RemoveObserver(observer);
 }
 
@@ skipping 53 matching lines @@
     providers_by_category_.erase(providers_it);
     categories_.erase(
         std::find(categories_.begin(), categories_.end(), category));
   } else {
     RegisterCategoryIfRequired(provider, category);
     DCHECK_EQ(new_status, provider->GetCategoryStatus(category));
   }
   NotifyCategoryStatusChanged(category);
 }
 
+void ContentSuggestionsService::OnSuggestionInvalidated(
+    ContentSuggestionsProvider* provider,
+    Category category,
+    const std::string& suggestion_id) {
+  RemoveSuggestionByID(category, suggestion_id);
+  FOR_EACH_OBSERVER(Observer, observers_,
+                    OnSuggestionInvalidated(category, suggestion_id));
+}
+
 bool ContentSuggestionsService::RegisterCategoryIfRequired(
     ContentSuggestionsProvider* provider,
     Category category) {
   auto it = providers_by_category_.find(category);
   if (it != providers_by_category_.end()) {
     DCHECK_EQ(it->second, provider);
     return false;
   }
 
   providers_by_category_[category] = provider;
   categories_.push_back(category);
   std::sort(categories_.begin(), categories_.end(),
             [this](const Category& left, const Category& right) {
               return category_factory_.CompareCategories(left, right);
             });
   if (IsCategoryStatusAvailable(provider->GetCategoryStatus(category))) {
     suggestions_by_category_.insert(
         std::make_pair(category, std::vector<ContentSuggestion>()));
   }
   return true;
 }
 
+bool ContentSuggestionsService::RemoveSuggestionByID(
+    Category category,
+    const std::string& suggestion_id) {
+  id_category_map_.erase(suggestion_id);
+  std::vector<ContentSuggestion>* suggestions =
+      &suggestions_by_category_[category];
+  auto position =
+      std::find_if(suggestions->begin(), suggestions->end(),
+                   [&suggestion_id](const ContentSuggestion& suggestion) {
+                     return suggestion_id == suggestion.id();
+                   });
+  if (position == suggestions->end())
+    return false;
+  suggestions->erase(position);
+  return true;
+}
+
 void ContentSuggestionsService::NotifyCategoryStatusChanged(Category category) {
   FOR_EACH_OBSERVER(
       Observer, observers_,
       OnCategoryStatusChanged(category, GetCategoryStatus(category)));
 }
 
 }  // namespace ntp_snippets