mus: Remove some dead code from client-lib.

components/mus/public/cpp/lib/window_tree_client_impl.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/mus/public/cpp/lib/window_tree_client_impl.h"
 
 #include "base/bind.h"
 #include "components/mus/common/util.h"
 #include "components/mus/public/cpp/lib/in_flight_change.h"
 #include "components/mus/public/cpp/lib/window_private.h"
@@ skipping 637 matching lines @@
       // the client applies the bounds we set below.
       window->SetSharedPropertyInternal(name, data.get());
     }
   }
   tree_->WmResponse(change_id, result);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // WindowTreeClientImpl, private:
 
-void WindowTreeClientImpl::OnActionCompleted(bool success) {
-  if (!change_acked_callback_.is_null())
-    change_acked_callback_.Run();
-}
-
 mojo::Callback<void(bool)> WindowTreeClientImpl::ActionCompletedCallback() {
-  return [this](bool success) { OnActionCompleted(success); };
+  return [this](bool success) {};
 }
 
 }  // namespace mus