chrome://snippets-internals page for debugging NTP snippets.

components/ntp_snippets/ntp_snippets_service.h

Index: components/ntp_snippets/ntp_snippets_service.h
diff --git a/components/ntp_snippets/ntp_snippets_service.h b/components/ntp_snippets/ntp_snippets_service.h
index d6ab94c7f476981938ea99aa637bbf7dcdba7623..dabc8e3c5d1f1da237f1d893d51e5ecccd374da5 100644
--- a/components/ntp_snippets/ntp_snippets_service.h
+++ b/components/ntp_snippets/ntp_snippets_service.h
@@ -75,11 +75,26 @@ class NTPSnippetsService : public KeyedService {
 
   // Fetches snippets from the server and adds them to the current ones.
   void FetchSnippets();
+  // Fetches snippets from the server for specified hosts (overriding
+  // suggestions from the suggestion service) and adds them to the current ones.
+  void FetchSnippetsFromHosts(const std::set<std::string>& hosts);
+  // Deletes all currently stored snippets.
+  void ClearSnippets();
 
   // Discards the snippet with the given |url|, if it exists. Returns true iff
   // a snippet was discarded.
   bool DiscardSnippet(const GURL& url);
 
+  // Returns the lists of snippets previously discarded by the user (that are
+  // not expired yet).
+  const NTPSnippetStorage& GetDiscardedSnippets();

[Marc Treib, 2016/04/13 08:45:52]

Should be const (add "const" just before the semicolon).
Also since this is a trivial getter, it should be called "discarded_snippets"
(yes it's weird and kinda inconsistent, but that's what the style guide
says...), and implemented inline here.

[jkrcal, 2016/04/14 15:27:00]

Done.

+
+  // Clears the lists of snippets previously discarded by the user.
+  void ClearDiscardedSnippets();
+
+  // Returns the lists of suggestion hosts the snippets are restricted to.
+  std::set<std::string> GetSuggestionsHosts();

[Marc Treib, 2016/04/13 08:45:52]

Also const please

[jkrcal, 2016/04/14 15:27:01]

Done.

+
   // Observer accessors.
   void AddObserver(NTPSnippetsServiceObserver* observer);
   void RemoveObserver(NTPSnippetsServiceObserver* observer);
@@ -107,8 +122,6 @@ class NTPSnippetsService : public KeyedService {
                     scoped_ptr<base::Value> parsed);
   void OnJsonError(const std::string& snippets_json, const std::string& error);
 
-  void FetchSnippetsImpl(const std::set<std::string>& hosts);
-
   // Expects a top-level dictionary containing a "recos" list, which will be
   // passed to LoadFromListValue().
   bool LoadFromValue(const base::Value& value);