Get rid of the EnableClose() infrastructure in Widget.

ui/views/widget/native_widget_private.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 UI_VIEWS_WIDGET_NATIVE_WIDGET_PRIVATE_H_
 #define UI_VIEWS_WIDGET_NATIVE_WIDGET_PRIVATE_H_
 #pragma once
 
 #include "base/string16.h"
 #include "ui/gfx/native_widget_types.h"
@@ skipping 154 matching lines @@
   virtual gfx::Rect GetWindowScreenBounds() const = 0;
   virtual gfx::Rect GetClientAreaScreenBounds() const = 0;
   virtual gfx::Rect GetRestoredBounds() const = 0;
   virtual void SetBounds(const gfx::Rect& bounds) = 0;
   virtual void SetSize(const gfx::Size& size) = 0;
   virtual void MoveAbove(gfx::NativeView native_view) = 0;
   virtual void MoveToTop() = 0;
   virtual void SetShape(gfx::NativeRegion shape) = 0;
   virtual void Close() = 0;
   virtual void CloseNow() = 0;
-  virtual void EnableClose(bool enable) = 0;
   virtual void Show() = 0;
   virtual void Hide() = 0;
   // Invoked if the initial show should maximize the window. |restored_bounds|
   // is the bounds of the window when not maximized.
   virtual void ShowMaximizedWithBounds(const gfx::Rect& restored_bounds) = 0;
   virtual void ShowWithWindowState(ui::WindowShowState show_state) = 0;
   virtual bool IsVisible() const = 0;
   virtual void Activate() = 0;
   virtual void Deactivate() = 0;
   virtual bool IsActive() const = 0;
@@ skipping 21 matching lines @@
   virtual void SetInactiveRenderingDisabled(bool value) = 0;
 
   // Overridden from NativeWidget:
   virtual internal::NativeWidgetPrivate* AsNativeWidgetPrivate() OVERRIDE;
 };
 
 }  // namespace internal
 }  // namespace views
 
 #endif  // UI_VIEWS_WIDGET_NATIVE_WIDGET_PRIVATE_H_