Use mojo Shelf interfaces for both mash and classic ash.

ash/shelf/shelf_view_unittest.cc

Index: ash/shelf/shelf_view_unittest.cc
diff --git a/ash/shelf/shelf_view_unittest.cc b/ash/shelf/shelf_view_unittest.cc
index ba3874cd940a920003188ed5917dc5a3e49fc0b3..561a4cd6ef4765109d83e57dbd85f4a6b96d4d73 100644
--- a/ash/shelf/shelf_view_unittest.cc
+++ b/ash/shelf/shelf_view_unittest.cc
@@ -250,18 +250,6 @@ class TestShelfDelegateForShelfView : public ShelfDelegate {
   void set_is_app_pinned(bool is_pinned) { is_app_pinned_ = is_pinned; }
 
   // ShelfDelegate overrides:
-  void OnShelfCreated(WmShelf* shelf) override {}
-
-  void OnShelfDestroyed(WmShelf* shelf) override {}
-
-  void OnShelfAlignmentChanged(WmShelf* shelf) override {}
-
-  void OnShelfAutoHideBehaviorChanged(WmShelf* shelf) override {}
-
-  void OnShelfAutoHideStateChanged(WmShelf* shelf) override {}
-
-  void OnShelfVisibilityStateChanged(WmShelf* shelf) override {}
-
   ShelfID GetShelfIDForAppID(const std::string& app_id) override {
     ShelfID id = 0;
     EXPECT_TRUE(base::StringToInt(app_id, &id));