WidgetDelegateView is its own contents view.

ash/mus/non_client_frame_controller.cc

 // Copyright 2015 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/mus/non_client_frame_controller.h"
 
 #include <stdint.h>
 
 #include <memory>
 #include <string>
@@ skipping 374 matching lines @@
 
   base::string16 title = window_->GetSharedProperty<base::string16>(
       ui::mojom::WindowManager::kWindowTitle_Property);
 
   if (IsWindowJanky(window_))
     title += base::ASCIIToUTF16(" !! Not responding !!");
 
   return title;
 }
 
-views::View* NonClientFrameController::GetContentsView() {
-  return this;
-}
-
 bool NonClientFrameController::CanResize() const {
   return window_ &&
          (GetResizeBehavior(window_) & ui::mojom::kResizeBehaviorCanResize) !=
              0;
 }
 
 bool NonClientFrameController::CanMaximize() const {
   return window_ &&
          (GetResizeBehavior(window_) & ui::mojom::kResizeBehaviorCanMaximize) !=
              0;
@@ skipping 49 matching lines @@
   }
 }
 
 void NonClientFrameController::OnWindowDestroyed(ui::Window* window) {
   window_->RemoveObserver(this);
   window_ = nullptr;
 }
 
 }  // namespace mus
 }  // namespace ash