WidgetDelegateView is its own contents view.

ash/shell/toplevel_window.cc

 // Copyright (c) 2012 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/shell/toplevel_window.h"
 
 #include "ash/common/wm/window_positioner.h"
 #include "ash/common/wm/window_state.h"
 #include "ash/shell.h"
 #include "ash/wm/window_state_aura.h"
@@ skipping 69 matching lines @@
     *show_state = saved_state->show_state;
   } else {
     // Initial default bounds.
     bounds->SetRect(10, 150, 300, 300);
   }
   WindowPositioner::GetBoundsAndShowStateForNewWindow(
       nullptr, is_saved_bounds, *show_state, bounds, show_state);
   return true;
 }
 
-views::View* ToplevelWindow::GetContentsView() {
-  return this;
-}
-
 bool ToplevelWindow::CanResize() const {
   return params_.can_resize;
 }
 
 bool ToplevelWindow::CanMaximize() const {
   return params_.can_maximize;
 }
 
 bool ToplevelWindow::CanMinimize() const {
   return params_.can_maximize;
 }
 
 }  // namespace shell
 }  // namespace ash