table: Carry v.u.generator down to populate_views()

The method is called by view_builder::consumer when building a view and
the consumer already has stable dependency reference on the view updates
generator.

Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>

db/view/view.cc

@@ -2295,7 +2295,6 @@ public:
         if (!step.current_key.key().is_empty(*_step.reader.schema())) {
             load_views_to_build();
         }
-        (void)_gen;
     }
 
     void load_views_to_build() {
@@ -2396,6 +2395,7 @@ public:
             auto close_reader = defer([&reader] { reader.close().get(); });
             reader.upgrade_schema(base_schema);
             _step.base->populate_views(
+                    _gen,
                     std::move(views),
                     _step.current_token(),
                     std::move(reader),

replica/database.hh

@@ -1051,6 +1051,7 @@ public:
 
     // Reader's schema must be the same as the base schema of each of the views.
     future<> populate_views(
+            shared_ptr<db::view::view_update_generator> gen,
             std::vector<db::view::view_and_base>,
             dht::token base_token,
             flat_mutation_reader_v2&&,

replica/table.cc

@@ -2107,6 +2107,7 @@ table::local_base_lock(
  * @return a future that resolves when the updates have been acknowledged by the view replicas
  */
 future<> table::populate_views(
+        shared_ptr<db::view::view_update_generator> gen,
         std::vector<db::view::view_and_base> views,
         dht::token base_token,
         flat_mutation_reader_v2&& reader,