chromeos: fix focus for mushrome

ash/aura/shell_port_classic.cc

 // Copyright 2016 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 "ash/aura/shell_port_classic.h"
 
 #include <utility>
 
 #include "ash/accelerators/accelerator_controller.h"
 #include "ash/accelerators/accelerator_controller_delegate_aura.h"
@@ skipping 259 matching lines @@
 
 std::unique_ptr<AcceleratorController>
 ShellPortClassic::CreateAcceleratorController() {
   DCHECK(!accelerator_controller_delegate_);
   accelerator_controller_delegate_ =
       base::MakeUnique<AcceleratorControllerDelegateAura>();
   return base::MakeUnique<AcceleratorController>(
       accelerator_controller_delegate_.get(), nullptr);
 }
 
+void ShellPortClassic::OnCreatedRootWindowContainers(
+    RootWindowController* root_window_controller) {}
+
 void ShellPortClassic::OnDisplayConfigurationChanging() {
   for (auto& observer : display_observers_)
     observer.OnDisplayConfigurationChanging();
 }
 
 void ShellPortClassic::OnDisplayConfigurationChanged() {
   for (auto& observer : display_observers_)
     observer.OnDisplayConfigurationChanged();
 }
 
 }  // namespace ash