Move OnURLsDeleted from NTPSnippetsService to ContentSuggestionsService

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 d479eeccee05250904c4996f9f25680e1076575f..309ce45ec9df20a76f462550917db1180e9e0bf8 100644
--- a/components/ntp_snippets/content_suggestions_provider.h
+++ b/components/ntp_snippets/content_suggestions_provider.h
@@ -101,6 +101,13 @@ class ContentSuggestionsProvider {
   virtual void FetchSuggestionImage(const std::string& suggestion_id,
                                     const ImageFetchedCallback& callback) = 0;
 
+  // Removes the given list of URLs and their associated data (depends on the
+  // provider) from all providers. Providers should immediately clear any

[vitaliii, 2016/09/02 12:38:30]

I am not sure about the wording.
Should it be "from all providers' internal storage"?

[Marc Treib, 2016/09/02 12:57:10]

See below - if possible, I'd like to merge this with ClearHistory below, since
it's essentially the same thing: "something got deleted from history, do
whatever you have to do in response to that".
Or am I missing something? If these two actually are significantly different,
then the comments need to make very clear what the difference is, and what is
expected of a provider in either case.

[vitaliii, 2016/09/02 14:13:16]

Done.

+  // history-related data associated with |deleted_urls| or all data if
+  // |all_history| is true.
+  virtual void RemoveURLsFromHistory(bool all_history,

[Marc Treib, 2016/09/02 12:57:10]

Hm, with all_history==true, isn't this essentially the same as a ClearHistory
call with appropriate begin/end parameters? Can we maybe map one to the other?
(e.g. the service could construct an appropriate filter function from
deleted_urls, and pass that to ClearHistory).
I'd prefer if we didn't have multiple history-clearing-related methods on this
interface.

[vitaliii, 2016/09/02 14:13:16]

Done.

+                                     const std::vector<GURL>& deleted_urls) = 0;
+
   // Removes history from the specified time range where the URL matches the
   // |filter|. The data removed depends on the provider. Note that the
   // data outside the time range may be deleted, for example suggestions, which