Ntp: show AllDismissedItem when all sections have been dismissed.

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 f52a9809d09dcae42dbad4cd9a62ff9598870423..e37e512de5938d8878d1803d6387aac508b930c0 100644
--- a/components/ntp_snippets/content_suggestions_service.cc
+++ b/components/ntp_snippets/content_suggestions_service.cc
@@ -150,11 +150,22 @@ void ContentSuggestionsService::DismissCategory(Category category) {
   if (providers_it == providers_by_category_.end())
     return;
 
+  dismissed_providers_by_category_[providers_it->first] = providers_it->second;
   providers_by_category_.erase(providers_it);
   categories_.erase(
       std::find(categories_.begin(), categories_.end(), category));

[Marc Treib, 2016/10/11 12:18:14]

I think we agreed to also clear suggestions_by_category_[category] here? It
should be rare that there's anything there at this point, but let's make sure
that our various data structures always stay consistent.

[Michael van Ouwerkerk, 2016/10/11 15:21:31]

Done.

 }
 
+void ContentSuggestionsService::RestoreDismissedCategories() {
+  auto dismissed_providers_by_category_copy = dismissed_providers_by_category_;

[Marc Treib, 2016/10/11 12:18:14]

nit: Add a comment on why the copy is needed?

[Michael van Ouwerkerk, 2016/10/11 15:21:31]

Done.

+  for (const auto& category_provider_pair :
+       dismissed_providers_by_category_copy) {
+    RegisterCategoryIfRequired(category_provider_pair.second,
+                               category_provider_pair.first);
+  }
+  dismissed_providers_by_category_.clear();

[Marc Treib, 2016/10/11 12:18:15]

Now it should already be empty at this point, right? If so, maybe just DCHECK
that?

[Michael van Ouwerkerk, 2016/10/11 15:21:31]

Done.

+}
+
 void ContentSuggestionsService::AddObserver(Observer* observer) {
   observers_.AddObserver(observer);
 }
@@ -274,6 +285,12 @@ bool ContentSuggestionsService::RegisterCategoryIfRequired(
     return false;
   }
 
+  auto dismissed_it = dismissed_providers_by_category_.find(category);
+  if (dismissed_it != dismissed_providers_by_category_.end()) {
+    DCHECK_EQ(dismissed_it->second, provider);
+    dismissed_providers_by_category_.erase(dismissed_it);
+  }
+
   providers_by_category_[category] = provider;
   categories_.push_back(category);
   SortCategories();