Adding ClearBlackList to the PreviewsBlackList and plumbing to UI

components/previews/core/previews_io_data.h

Index: components/previews/core/previews_io_data.h
diff --git a/components/previews/core/previews_io_data.h b/components/previews/core/previews_io_data.h
index ce157858d5a44171cb5c1728a2db8ae5c98f5529..5f1efd09b6bd53a8c5f87e5f6021122127f08d20 100644
--- a/components/previews/core/previews_io_data.h
+++ b/components/previews/core/previews_io_data.h
@@ -5,41 +5,52 @@
 #ifndef COMPONENTS_PREVIEWS_CORE_PREVIEWS_IO_DATA_H_
 #define COMPONENTS_PREVIEWS_CORE_PREVIEWS_IO_DATA_H_
 
 #include <memory>
 #include <string>
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "base/single_thread_task_runner.h"
+#include "base/time/time.h"
 #include "components/previews/core/previews_opt_out_store.h"
 
+class GURL;
+
 namespace previews {
 class PreviewsBlackList;
 class PreviewsUIService;
 
 // A class to manage the IO portion of inter-thread communication between
 // previews/ objects. Created on the UI thread, but used only on the IO thread
 // after initialization.
 class PreviewsIOData {
  public:
   PreviewsIOData(
       const scoped_refptr<base::SingleThreadTaskRunner>& ui_task_runner,
       const scoped_refptr<base::SingleThreadTaskRunner>& io_task_runner);
   virtual ~PreviewsIOData();
 
   // Stores |previews_ui_service| as |previews_ui_service_| and posts a task to
   // InitializeOnIOThread on the IO thread.
   void Initialize(base::WeakPtr<PreviewsUIService> previews_ui_service,
                   std::unique_ptr<PreviewsOptOutStore> previews_opt_out_store);
 
+  // Adds a navigation to |url| to the black list with result |opt_out|.
+  void AddPreviewNavigation(const GURL& url, bool opt_out, PreviewsType type);
+
+  // Clears the history of the black list between |begin_time| and |end_time|,
+  // both inclusive.
+  void ClearBlackList(base::Time begin_time, base::Time end_time);
+
+  // The previews black list that decides whether a navigation can use previews.
   PreviewsBlackList* black_list() const { return previews_black_list_.get(); }
 
  protected:
   // Posts a task to SetIOData for |previews_ui_service_| on the UI thread with
   // a weak pointer to |this|. Virtualized for testing.
   virtual void InitializeOnIOThread(
       std::unique_ptr<PreviewsOptOutStore> previews_opt_out_store);
 
  private:
   // The UI thread portion of the inter-thread communication for previews.