Use mojo Shelf interfaces for both mash and classic ash.

ash/common/shelf/shelf_delegate.h

Index: ash/common/shelf/shelf_delegate.h
diff --git a/ash/common/shelf/shelf_delegate.h b/ash/common/shelf/shelf_delegate.h
index 9d61be4c833061ac821feb3d1796706923c723cf..dbfe62741567c6e6cda1e6ba5021ac62c53a2ea5 100644
--- a/ash/common/shelf/shelf_delegate.h
+++ b/ash/common/shelf/shelf_delegate.h
@@ -19,26 +19,6 @@ class ASH_EXPORT ShelfDelegate {
  public:
   virtual ~ShelfDelegate() {}
 
-  // Callback used to allow delegate to perform initialization actions that
-  // depend on the Shelf being in a known state.
-  virtual void OnShelfCreated(WmShelf* shelf) = 0;
-
-  // Callback used to inform the delegate that a specific shelf no longer
-  // exists.
-  virtual void OnShelfDestroyed(WmShelf* shelf) = 0;
-
-  // Called when |shelf|'s alignment changes.
-  virtual void OnShelfAlignmentChanged(WmShelf* shelf) = 0;
-
-  // Called when |shelf|'s auto-hide behavior changes.
-  virtual void OnShelfAutoHideBehaviorChanged(WmShelf* shelf) = 0;
-
-  // Called when |shelf|'s auto-hide state changes.
-  virtual void OnShelfAutoHideStateChanged(WmShelf* shelf) = 0;
-
-  // Called when |shelf|'s visibility state is committed.
-  virtual void OnShelfVisibilityStateChanged(WmShelf* shelf) = 0;
-
   // Get the shelf ID from an application ID.
   virtual ShelfID GetShelfIDForAppID(const std::string& app_id) = 0;