Use mojo Shelf interfaces for both mash and classic ash.

ash/test/test_shelf_delegate.h

Index: ash/test/test_shelf_delegate.h
diff --git a/ash/test/test_shelf_delegate.h b/ash/test/test_shelf_delegate.h
index 56aa1a135b49171d9e353a4b3bc06244d2297821..7fe5989da4adcb74cf98ad6e5100843dd8c8452c 100644
--- a/ash/test/test_shelf_delegate.h
+++ b/ash/test/test_shelf_delegate.h
@@ -50,12 +50,6 @@ class TestShelfDelegate : public ShelfDelegate, public aura::WindowObserver {
   void OnWindowHierarchyChanging(const HierarchyChangeParams& params) override;
 
   // ShelfDelegate implementation.
-  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 GetShelfIDForAppIDAndLaunchID(const std::string& app_id,
                                         const std::string& launch_id) override;