[NTP::PhysicalWeb] Implement suggestion dismissal.

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 92ef4b46aea07264201b3124a229e25d8fc8cab1..08504f6c266ef4301720d05bc0509c4c03993a84 100644
--- a/components/ntp_snippets/content_suggestions_service.cc
+++ b/components/ntp_snippets/content_suggestions_service.cc
@@ -168,10 +168,7 @@ void ContentSuggestionsService::DismissSuggestion(
       suggestion_id);
 
   // Remove the suggestion locally.
-  bool removed = RemoveSuggestionByID(suggestion_id);
-  DCHECK(removed) << "The dismissed suggestion " << suggestion_id
-                  << " has already been removed. Providers must not call"
-                  << " OnNewSuggestions in response to DismissSuggestion.";
+  RemoveSuggestionByID(suggestion_id);

[jkrcal, 2016/12/07 14:20:01]

Why did you remove the DCHECK?

[vitaliii, 2016/12/08 07:13:41]

Because of it one could not dismiss suggestions obtained through "More" action
(i.e. through |Fetch| call). Previously, the "More" action was used only for
articles and added suggestions were propagated to new NTPs through
OnNewSuggestions, so this DCHECK did not fire. However, in Physical Web provider
the suggestions are not propagated to new NTPs and this DCHECK fires.

[jkrcal, 2016/12/08 09:55:42]

Ok, please expand the comment.

[vitaliii, 2016/12/08 11:05:29]

Done.

 }
 
 void ContentSuggestionsService::DismissCategory(Category category) {