Change NTPSnippetsBridge to read from ContentSuggestionsService

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 3ce179f48df90fd5b6e6555960d86e1302e6e683..aaf2e80b5cf8cdc5a535313d2636003cfc5e0ff1 100644
--- a/components/ntp_snippets/content_suggestions_service.cc
+++ b/components/ntp_snippets/content_suggestions_service.cc
@@ -106,7 +106,10 @@ void ContentSuggestionsService::DiscardSuggestion(
                    [&suggestion_id](const ContentSuggestion& suggestion) {
                      return suggestion_id == suggestion.id();
                    });
-  DCHECK(position != suggestions->end());
+  DCHECK(position != suggestions->end())
+      << "The discarded suggestion " << suggestion_id
+      << " has already been removed. Providers must not call OnNewSuggestions"
+         " in response to DiscardSuggestion.";
   suggestions->erase(position);
 }