Consolidate ShouldUseNativeFrame/AlwaysUseNativeFrame/UseNativeFrame spaghetti.

views/window/native_window_delegate.h

 // Copyright (c) 2011 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.
 
 #ifndef VIEWS_WIDGET_NATIVE_WINDOW_DELEGATE_H_
 #define VIEWS_WIDGET_NATIVE_WINDOW_DELEGATE_H_
 #pragma once
 
 namespace ui {
 class ThemeProvider;
@@ skipping 17 matching lines @@
 
   virtual bool IsInactiveRenderingDisabled() const = 0;
   virtual void EnableInactiveRendering() = 0;
 
   // Returns true if the window is modal.
   virtual bool IsModal() const = 0;
 
   // Returns true if the window is a dialog box.
   virtual bool IsDialogBox() const = 0;
 
-  // Returns true if the window is using a system native frame. Returns false if
-  // it is rendering its own title bar, borders and controls.
-  virtual bool IsUsingNativeFrame() const = 0;
-
   // Returns the smallest size the window can be resized to by the user.
   virtual gfx::Size GetMinimumSize() const = 0;
 
   // Returns the non-client component (see views/window/hit_test.h) containing
   // |point|, in client coordinates.
   virtual int GetNonClientComponent(const gfx::Point& point) const = 0;
 
   // Runs the specified native command. Returns true if the command is handled.
   virtual bool ExecuteCommand(int command_id) = 0;
 
@@ skipping 21 matching lines @@
   virtual Window* AsWindow() = 0;
 
   //
   virtual NativeWidgetDelegate* AsNativeWidgetDelegate() = 0;
 };
 
 }  // namespace internal
 }  // namespace views
 
 #endif  // VIEWS_WIDGET_NATIVE_WINDOW_DELEGATE_H_