Add ClearHistory() to ContentSuggestionsService and its providers

components/ntp_snippets/content_suggestions_provider.h

Index: components/ntp_snippets/content_suggestions_provider.h
diff --git a/components/ntp_snippets/content_suggestions_provider.h b/components/ntp_snippets/content_suggestions_provider.h
index 36cc5fbfcd058bd91252c109309453c6d930247c..bcad4ff202ec989f42b9164b34a00b1c32ad564d 100644
--- a/components/ntp_snippets/content_suggestions_provider.h
+++ b/components/ntp_snippets/content_suggestions_provider.h
@@ -101,6 +101,16 @@ class ContentSuggestionsProvider {
   virtual void FetchSuggestionImage(const std::string& suggestion_id,
                                     const ImageFetchedCallback& callback) = 0;
 
+  // Removes history from a given time range related to URLs matched by
+  // |filter|. The data removed depends on the provider. Note that the
+  // data outside the time range may be deleted, for example suggestions, which
+  // are based on history from that time range. Providers should immediately
+  // clear any data related to history from the specified time range and URLs
+  // matched by |filter|.

[Marc Treib, 2016/08/30 13:01:56]

It's really an intersection between the time range and the filter, right? I.e.
remove everything that is in that range and that also matches the filter? Then
I'd say something like
"..from the specified time range where the URL matches the |filter|."

[vitaliii, 2016/08/30 14:17:48]

Done.

+  virtual void ClearHistory(base::Time begin,
+                            base::Time end,
+                            base::Callback<bool(const GURL& url)> filter) = 0;
+
   // Clears all caches for the given category, so that the next fetch starts
   // from scratch.
   virtual void ClearCachedSuggestions(Category category) = 0;