WidgetDelegateView is its own contents view.

ui/views/widget/widget_unittest.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 <algorithm>
 #include <memory>
 #include <set>
 
 #include "base/bind.h"
 #include "base/macros.h"
@@ skipping 1968 matching lines @@
 }
 
 #endif  // !defined(OS_MACOSX) || defined(USE_AURA)
 
 // See description of RunGetNativeThemeFromDestructor() for details.
 class GetNativeThemeFromDestructorView : public WidgetDelegateView {
  public:
   GetNativeThemeFromDestructorView() {}
   ~GetNativeThemeFromDestructorView() override { VerifyNativeTheme(); }
 
-  View* GetContentsView() override { return this; }
-
  private:
   void VerifyNativeTheme() {
     ASSERT_TRUE(GetNativeTheme() != NULL);
   }
 
   DISALLOW_COPY_AND_ASSIGN(GetNativeThemeFromDestructorView);
 };
 
 // Verifies GetNativeTheme() from the destructor of a WidgetDelegateView doesn't
 // crash. |is_first_run| is true if this is the first call. A return value of
@@ skipping 1827 matching lines @@
     Transparency_DesktopWidgetTranslucent
 #endif
 TEST_F(CompositingWidgetTest, MAYBE_Transparency_DesktopWidgetTranslucent) {
   CheckAllWidgetsForOpacity(Widget::InitParams::TRANSLUCENT_WINDOW);
 }
 
 #endif  // !defined(OS_CHROMEOS)
 
 }  // namespace test
 }  // namespace views