Remove all ReadingList entries on managed account signout.

components/reading_list/ios/reading_list_model.h

Index: components/reading_list/ios/reading_list_model.h
diff --git a/components/reading_list/ios/reading_list_model.h b/components/reading_list/ios/reading_list_model.h
index 44d8173e8df1f3b02a7dd99b79ddf1282147ed9e..42e536f8ef92bac6638f66f2bac31c92c9af3480 100644
--- a/components/reading_list/ios/reading_list_model.h
+++ b/components/reading_list/ios/reading_list_model.h
@@ -69,6 +69,10 @@ class ReadingListModel : public base::NonThreadSafe {
   // Mark all unseen entries as unread.
   virtual void MarkAllSeen() = 0;
 
+  // Delete all the Reading List entries. Return true if entries where indeed
+  // deleted.
+  virtual bool DeleteAllEntries() = 0;
+
   // Returns the flag about unseen entries on the device.
   // This flag is raised if some unseen items are added on this device.
   // The flag is reset if |ResetLocalUnseenFlag| is called or if all unseen