Refactor ViewsDelegate singleton

ui/views/widget/widget.cc

 // Copyright (c) 2012 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/widget/widget.h"
 
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/trace_event/trace_event.h"
@@ skipping 296 matching lines @@
   InitParams params = in_params;
 
   params.child |= (params.type == InitParams::TYPE_CONTROL);
   is_top_level_ = !params.child;
 
   if (params.opacity == views::Widget::InitParams::INFER_OPACITY &&
       params.type != views::Widget::InitParams::TYPE_WINDOW &&
       params.type != views::Widget::InitParams::TYPE_PANEL)
     params.opacity = views::Widget::InitParams::OPAQUE_WINDOW;
 
-  if (ViewsDelegate::views_delegate)
-    ViewsDelegate::views_delegate->OnBeforeWidgetInit(&params, this);
+  if (ViewsDelegate::GetInstance())
+    ViewsDelegate::GetInstance()->OnBeforeWidgetInit(&params, this);
 
   if (params.opacity == views::Widget::InitParams::INFER_OPACITY)
     params.opacity = views::Widget::InitParams::OPAQUE_WINDOW;
 
   bool can_activate = false;
   if (params.activatable != InitParams::ACTIVATABLE_DEFAULT) {
     can_activate = (params.activatable == InitParams::ACTIVATABLE_YES);
   } else if (params.type != InitParams::TYPE_CONTROL &&
              params.type != InitParams::TYPE_POPUP &&
              params.type != InitParams::TYPE_MENU &&
@@ skipping 559 matching lines @@
 
 void Widget::ClearNativeFocus() {
   native_widget_->ClearNativeFocus();
 }
 
 NonClientFrameView* Widget::CreateNonClientFrameView() {
   NonClientFrameView* frame_view =
       widget_delegate_->CreateNonClientFrameView(this);
   if (!frame_view)
     frame_view = native_widget_->CreateNonClientFrameView();
-  if (!frame_view && ViewsDelegate::views_delegate) {
+  if (!frame_view && ViewsDelegate::GetInstance()) {
     frame_view =
-        ViewsDelegate::views_delegate->CreateDefaultNonClientFrameView(this);
+        ViewsDelegate::GetInstance()->CreateDefaultNonClientFrameView(this);
   }
   if (frame_view)
     return frame_view;
 
   CustomFrameView* custom_frame_view = new CustomFrameView;
   custom_frame_view->Init(this);
   return custom_frame_view;
 }
 
 bool Widget::ShouldUseNativeFrame() const {
@@ skipping 619 matching lines @@
 
 ////////////////////////////////////////////////////////////////////////////////
 // internal::NativeWidgetPrivate, NativeWidget implementation:
 
 internal::NativeWidgetPrivate* NativeWidgetPrivate::AsNativeWidgetPrivate() {
   return this;
 }
 
 }  // namespace internal
 }  // namespace views