Get rid of the EnableClose() infrastructure in Widget.

ui/views/window/custom_frame_view.cc

 // 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.
 
 #include "ui/views/window/custom_frame_view.h"
 
 #include <algorithm>
 
 #include "base/utf_string_conversions.h"
 #include "grit/ui_resources.h"
@@ skipping 174 matching lines @@
 
 void CustomFrameView::GetWindowMask(const gfx::Size& size,
                                     gfx::Path* window_mask) {
   DCHECK(window_mask);
   if (frame_->IsMaximized())
     return;
 
   views::GetDefaultWindowMask(size, window_mask);
 }
 
-void CustomFrameView::EnableClose(bool enable) {
-  close_button_->SetEnabled(enable);
-}
-
 void CustomFrameView::ResetWindowControls() {
   restore_button_->SetState(CustomButton::BS_NORMAL);
   minimize_button_->SetState(CustomButton::BS_NORMAL);
   maximize_button_->SetState(CustomButton::BS_NORMAL);
   // The close button isn't affected by this constraint.
 }
 
 void CustomFrameView::UpdateWindowIcon() {
   window_icon_->SchedulePaint();
 }
@@ skipping 391 matching lines @@
     title_font_ = new gfx::Font(NativeWidgetWin::GetWindowTitleFont());
 #elif defined(OS_LINUX)
     // TODO(ben): need to resolve what font this is.
     title_font_ = new gfx::Font();
 #endif
     initialized = true;
   }
 }
 
 }  // namespace views