WidgetDelegateView is its own contents view.

ash/shell/widgets.cc

Index: ash/shell/widgets.cc
diff --git a/ash/shell/widgets.cc b/ash/shell/widgets.cc
index e62343bcb341c1ec5e9fddcdd6fd2e5203153cc0..a302bd06c16cb4f4075f122b882f15a8369f70ec 100644
--- a/ash/shell/widgets.cc
+++ b/ash/shell/widgets.cc
@@ -35,7 +35,6 @@ class WidgetsWindow : public views::WidgetDelegateView {
   gfx::Size GetPreferredSize() const override;
 
   // Overridden from views::WidgetDelegate:
-  views::View* GetContentsView() override;
   base::string16 GetWindowTitle() const override;
   bool CanResize() const override;
 
@@ -119,10 +118,6 @@ gfx::Size WidgetsWindow::GetPreferredSize() const {
   return gfx::Size(kWindowWidth, kWindowHeight);
 }
 
-views::View* WidgetsWindow::GetContentsView() {
-  return this;
-}
-
 base::string16 WidgetsWindow::GetWindowTitle() const {
   return base::ASCIIToUTF16("Examples: Widgets");
 }