Add ClearHistory() to ContentSuggestionsService and its providers

components/ntp_snippets/content_suggestions_service.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef COMPONENTS_NTP_SNIPPETS_CONTENT_SUGGESTIONS_SERVICE_H_
 #define COMPONENTS_NTP_SNIPPETS_CONTENT_SUGGESTIONS_SERVICE_H_
 
 #include <map>
 #include <memory>
 #include <string>
 #include <vector>
 
 #include "base/callback_forward.h"
 #include "base/observer_list.h"
 #include "base/optional.h"
+#include "base/time/time.h"
 #include "components/keyed_service/core/keyed_service.h"
 #include "components/ntp_snippets/category_factory.h"
 #include "components/ntp_snippets/category_status.h"
 #include "components/ntp_snippets/content_suggestions_provider.h"
 
 namespace gfx {
 class Image;
 }
 
 namespace ntp_snippets {
@@ skipping 87 matching lines @@
 
   // Observer accessors.
   void AddObserver(Observer* observer);
   void RemoveObserver(Observer* observer);
 
   // Registers a new ContentSuggestionsProvider. It must be ensured that at most
   // one provider is registered for every category and that this method is
   // called only once per provider.
   void RegisterProvider(std::unique_ptr<ContentSuggestionsProvider> provider);
 
+  // Removes history from all providers from a given time range. The data
+  // removed depends on a provider. Note that the data outside the time range
+  // may be deleted, for example suggestions, which are based on the time range.
+  // Providers should immediately clear any specified time range history-related
+  // data, such as (possibly dismissed) suggestions for NTPSnippetsService or in
+  // case of BookmarkSuggestionsProvider last visit dates.
+  void ClearHistory(base::Time begin, base::Time end);
+
   // Removes all suggestions from all caches or internal stores in all
   // providers. See |ClearCachedSuggestions|.
   void ClearAllCachedSuggestions();
 
   // Removes all suggestions of the given |category| from all caches or internal
   // stores in the service and the corresponding provider. It does, however, not
   // remove any suggestions from the provider's sources, so if its configuration
   // hasn't changed, it might return the same results when it fetches the next
   // time. In particular, calling this method will not mark any suggestions as
   // dismissed.
@@ skipping 96 matching lines @@
   // background fetching and debugging calls to it. If the NTPSnippetsService is
   // loaded, it is also present in |providers_|, otherwise this is a nullptr.
   NTPSnippetsService* ntp_snippets_service_;
 
   DISALLOW_COPY_AND_ASSIGN(ContentSuggestionsService);
 };
 
 }  // namespace ntp_snippets
 
 #endif  // COMPONENTS_NTP_SNIPPETS_CONTENT_SUGGESTIONS_SERVICE_H_