mash: Preliminary support for shelf auto-hide

ash/shelf/shelf_delegate.h

Index: ash/shelf/shelf_delegate.h
diff --git a/ash/shelf/shelf_delegate.h b/ash/shelf/shelf_delegate.h
index 16e041c4e454904b0b68dcd2282c408ac5513c33..fa0988e3d5e826a4c366d3b58178c9ec817b8db1 100644
--- a/ash/shelf/shelf_delegate.h
+++ b/ash/shelf/shelf_delegate.h
@@ -31,6 +31,12 @@ class ASH_EXPORT ShelfDelegate {
   // Called when |shelf|'s auto-hide behavior changes.
   virtual void OnShelfAutoHideBehaviorChanged(Shelf* shelf) = 0;
 
+  // Called when |shelf|'s auto-hide state changes.
+  virtual void OnShelfAutoHideStateChanged(Shelf* shelf) = 0;
+
+  // Called when |shelf|'s visibility state is committed.
+  virtual void OnShelfVisibilityStateChanged(Shelf* shelf) = 0;
+
   // Get the shelf ID from an application ID.
   virtual ShelfID GetShelfIDForAppID(const std::string& app_id) = 0;