MacViews: Fixed BrowserViewTest.CloseWithTabsStartWithActive.

ui/views/widget/native_widget_mac.h

Index: ui/views/widget/native_widget_mac.h
diff --git a/ui/views/widget/native_widget_mac.h b/ui/views/widget/native_widget_mac.h
index 93402a18470462c13c145d15fe0c2b9975fe9057..cf64ee05515c1f8e5d10c1ccd88f7e86bce12122 100644
--- a/ui/views/widget/native_widget_mac.h
+++ b/ui/views/widget/native_widget_mac.h
@@ -38,10 +38,8 @@ class VIEWS_EXPORT NativeWidgetMac : public internal::NativeWidgetPrivate {
   bool IsWindowModalSheet() const;
 
   // Deletes |bridge_| and informs |delegate_| that the native widget is
-  // destroyed.
-  // This is usually called from the NSWindowDelegate. A derived class can
-  // override this method for an early hook into the native window teardown.
-  virtual void OnWindowWillClose();
+  // destroyed. This is usually called from the NSWindowDelegate.
+  void OnWindowWillClose();
 
   // Returns the vertical position that sheets should be anchored, in pixels
   // from the bottom of the window.