Remove deleted offline page suggestions from opened NTPs

components/ntp_snippets/content_suggestions_service.cc

Index: components/ntp_snippets/content_suggestions_service.cc
diff --git a/components/ntp_snippets/content_suggestions_service.cc b/components/ntp_snippets/content_suggestions_service.cc
index 7b23609c6a01f0babb79428bd55cb676c26393ac..3059437c9e3479ccd30d8294bfd17ab3dc177297 100644
--- a/components/ntp_snippets/content_suggestions_service.cc
+++ b/components/ntp_snippets/content_suggestions_service.cc
@@ -141,19 +141,10 @@ void ContentSuggestionsService::DismissSuggestion(
   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) {
@@ -227,6 +218,16 @@ void ContentSuggestionsService::OnCategoryStatusChanged(
   NotifyCategoryStatusChanged(category);
 }
 
+void ContentSuggestionsService::OnSuggestionInvalidated(
+    ContentSuggestionsProvider* provider,
+    Category category,
+    const std::string& suggestion_id) {
+  if (RemoveSuggestionByID(category, suggestion_id)) {
+    FOR_EACH_OBSERVER(Observer, observers_,

[Marc Treib, 2016/08/16 09:03:53]

Wouldn't we want to send the invalidation anyway? Even if the suggestion isn't
in the service's store anymore, it might still be shown in the UI.

[Philipp Keck, 2016/08/16 10:54:40]

Yes, right. Done.

+                      OnSuggestionInvalidated(category, suggestion_id));
+  }
+}
+
 bool ContentSuggestionsService::RegisterCategoryIfRequired(
     ContentSuggestionsProvider* provider,
     Category category) {
@@ -249,6 +250,23 @@ bool ContentSuggestionsService::RegisterCategoryIfRequired(
   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_,